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Plate 






DESCRIPTION OF THE CHROMOLITHOGRAPHS. 



PLATE I. 

Fk;. 1. — Semi-schematic representation of the papilla of an eye which 
is myopic in a moderate degree. The colored plate is taken from 
nature : the lower gives a schematic section of the same optic nerve. 
(Landolt, Refraction and Accommodation of the Eye, page 427.) 

/'.V. crescent; PI'', pigmented circle, corresponding to the choroidal 
ring; N, outline of the optic nerve; S, super-traction of the inner 
part of the retina; ]'. vein passing over it; H, hilus of the central 
vessels, covered by the overlapping retina. The inner and outer 
sheaths of the optic nerve are noticeably separated from each other. 

Fig. 2. — -Normal fundus oculi in an individual with light-brown hair. 
(Jaeger, Beitrage zur Pathologie des Auges, Taf. I.) 

Fig. 3. — Upright image of an astigmatic eye. (Ophthalmoskopiseher 
Hand-Atlas von Eduard von Jaeger. Neu bearbeitet von Dr. 

Maximilian Salzmann, Taf. V.. Fig. 31.) 



PLATE II. 



Fk;. 1. — Congenital excavation of the nerve-head. (Jaeger, loc. cit., 
Taf. X I . 

Fio. :2. — Glaucomatous excavation of the nerve-head. (Jaeger. Inc. 
rit.. Taf. XIX.j 

Fig, 3. — Optic neuritis (papillitis). Right optic disc of a patient suf- 
fering probably from a cerebral tumor. (Gowers's Medical Oph- 
thalmoscopy, Pi. I.. Fig. G.) 

Fig. 4. — Atrophy of the optic nerve ; right eye. The duration of the 
disease was three years. The patient presented slight spinal 
symptoms. (Gowers, loc. cit., PI. II., Fig. 6.) 



Plare 





DISEASES 



THE EYE. 



A HANDBOOK OF OPHTHALMIC PRACTICE, 



STUDENTS AND PKACTITiONERS. 



BY 

G. E. de SCHWEINITZ, A. M., M. D., 

PROFESSOR OF OPHTHALMOLOGY IN THE JEFFERSON MEDICAL COLLEGE; PROFESSOR OF 

DISEASES OF THE EYE IN THE PHILADELPHIA POLYCLINIC: OPHTHALMIC SURGEON 

TO THE PHILADELPHIA HOSPITAL, TO THE CHILDREN'S HOSPITAL, AND TO 

THE METHODIST HOSPITAL; OPHTHALMOLOGIST TO THE 

ORTHOPEDIC HOSPITAL AND INFIRMARY 

FOR NERVOUS DISEASES. 



WITH 256 ILLUSTRATIONS AND TWO CHROMOLITHOGRAPHIC PLATES. 



SECOND EDITION, THOROUGHLY REVISED. 



PHILADELPHIA : 
W. B. SAUNDERS, 

925 Walnut Street. 
1896. 



Copyright, 1896, 
BY W. B. SAUNDERS. 






&%Wt4 









> 



- 



ELECTROTYPED BY 
WESTCOTT & THOMSON, PHILADA. 



PRESS OF 
W. B. SAUNDERS, PHILADA. 



PREFACE TO THE SECOND EDITION. 



The favorable reception accorded to the first edition, as well 
as to the supplementary edition two years later, has encouraged 
the author to submit the entire book to a thorough revision, with 
the hope that it may continue to find favor with the students 
and practitioners for whom it was written. 

In addition to this general revision, special paragraphs on 
the following new matter have been introduced : Filamentous 
Keratitis, Blood-staining of the Cornea, Esseutial Phthisis 
Bulbi, Foreign Bodies in the Lens, Circinate Retinitis, Sym- 
metrical Changes at the Macula Lutea in Infancy, Hyaline 
Bodies (Drusen) in the Papilla, Monocular Diplopia, Subcon- 
junctival Injections of Germicides, Infiltration-Anaesthesia, and 
Sterilization of Collyria. Brief mention of Ophthalmia Nodosa, 
Electric Ophthalmia, and Angioid Streaks in the Retina also finds 
place. 

For the bibliography of the first edition an appendix has been 
substituted which contains a full description of the method of 
determining the corneal astigmatism with the ophthalmometer 
of Javal and Schiotz, and the rotations of the eyes with the 
tropometer of Stevens. 

The chapter on Operations has been enlarged and rewritten. 
The book has been enriched with forty additional illustrations. 

The author is greatly indebted to his colleague, Dr. Edward 
Jackson, for his revision of the chapters on General Optical 
Principles and Xormal and Abnormal Refraction, and for his 

7 



8 PREFACE. 

recast of the section on Retinoscopy, which he had contributed 
to the first edition. 

Messrs. J. H. Gemrig & Son of Philadelphia have very kindly 
furnished most of the cuts of instruments which illustrate the 
chapter on Operations. For the remainder, as well as for the 
illustrations of the ophthalmometer and the tropometer, the 
author is indebted to E. B. Meyrowitz of New York. 

Philadelphia: 1401 Locust St. 
April, 1896. 



PREFACE. 



This book has been written in the hope that it may prove 
of service to students and practitioners who desire to begin 
the study of ophthalmology. 

The methods of examining eyes, and the symptoms, diag- 
nosis and treatment of ocular diseases have received the 
largest share of attention. The subject-matter has been given 
in greater detail than is customary in books written for 
students, because the author has been led to believe by those 
whom he has had the privilege of instructing in the Medical 
Department of the University of Pennsylvania, in the Phila- 
delphia Polyclinic, and in the wards of the Philadelphia 
Hospital, that this presentation of the practice of ophthal- 
mic science and the systematic examination of cases would be 
acceptable. 

Certain illustrations, descriptions, and classifications taken 
from standard text-books and monographs, which have proved 
of special service in teaching students, have also been incor- 
porated. These are properly acknowledged in the text, and 
a list of the books and brochures which have been con- 
stantly consulted during the preparation of these pages is also 
appended. Some previous writings of the author — Affections of 



10 PREFACE. 

the Eyelids, Lachrymal Apparatus, Conjunctiva, and Cornea, 
in Keating's Cyclopaedia of Diseases of Children, Vol. IV.; 
Congenital Anomalies of the Eye, in Hirst's System of Obstet- 
rics, Vol. II.; and Diseases of the Eye (Revision of the 
chapter) in Ashhurst's Principles and Practice of Surgery 
(Fifth Edition) — have also been utilized. 

Dr. James Wallace, Chief of the Eye Dispensary of the 
University Hospital, has written Chapters I. and IV. ; that 
portion of Chapter III. which relates to reflection, the oph- 
thalmoscope and its theory, and the explanation of the direct 
and indirect method ; and that part of Chapter XIX. which 
describes the mechanism of diplopia, the rotation of the eyeball 
around the visual line, and the causes of concomitant convergent 
and divergent squint. He has also given valuable advice and 
assistance in reading the sheets for the press. Dr. Edward 
Jackson, Professor of Ophthalmology in the Philadelphia 
Polyclinic, has written the section on Retinoscopy. The author 
is indebted to these gentlemen for their aid, and for the pre- 
sentation of the subjects entrusted to them in a manner 
which, he feels sure, will be satisfactory to students. 

Messrs. J. H. Gemrig and Son have very kindly furnished 
the cuts of the instruments which illustrate the chapter on 
Operations. 



Philadelphia : 1401 Locust St., 
March, 1892. 



CONTENTS. 



CHAPTER I. 

GENERAL, OPTICAL PRINCIPLES. 

PAGE 

Refraction — Index of Refraction — Prisms — Refraction through a Prism — 
Angle of Deviation — Limit-angle of Refraction — Internal Reflection — 
Numbering Prisms — Rays of Light — Lenses — Foci of Convex Lenses — 
Foci of Concave Lenses — Formation of Images by Lenses — Focal Dis- 
tance of a Lens — Numeration of Lenses — Spherical Lenses — Cylindrical 
Lenses — Combination of Lenses — Visual Angle — Visual Acuteness — 
Limit of Perception — Normal Acuteness of Vision — Accommodation — 
Angle Gamma — Angle Alpha — Convergence — Metre- Angle . . . 17-56 

CHAPTER II. 

EXAMINATION OF THE PATIENT AND EXTERNAL EXAMINATION OF 

THE EYE. 

Direct Inspection of the Eye — Bloodvessels of the Conjunctiva — Inspec- 
tion of the Cornea — Oblique Illumination — The Corneal Loupe — The 
Color of the Iris — The Pupil — Mobility of the Iris — Diliataton of the 
Pupil — Contraction of the Pupil — Unequal Pupils — Testing Acuteness 
of Vision — Light-sense — Color-sense — Method of Holmgren — Method 
of Thomson — Lantern-test — Pseudo-isochromatic Plates of Stilling — 
Accommodation — Mobility of the Eyes — Balance of the External Eye 
Muscles — Heterophoria — Esophoria — Exophoria — Cyclophoria — Hy- 
perphoria — Power of Convergence — Field of Vision — Tension — Prop- 
tosis — Position of the Eyes 57-91 

CHAPTER III. 

REFLECTION. THE OPHTHALMOSCOPE AND ITS THEORY. OPHTHAL- 
MOSCOPY AND RETINOSCOPY. 

Reflection — The Ophthalmoscope — Direct Method — Indirect Method — 
Ophthalmoscopy — Direct Method of Ophthalmoscopy — Examination 
of the Cornea and Lens — Examination of the Vitreous — Examination 

11 



12 CONTENTS. 

PAGE 

of the Transparent Media with Reference to the Position of Opacities 
— The Normal Fundus Oculi — The Optic Nerve — The Bloodvessels — 
The Retina — The Macula Lutea — The Choroid — Determination of 
Refraction by the Ophthalmoscope — Ophthalmoscopy by the Indirect 
Method — Estimation of Refraction by the Indirect Method — Estimation 
of Astigmatism by the Inverted Image — Ophthalmometry — Optometry 
— Retinoscopy — The Use of Mydriatics 92-138 

CHAPTER IV. 

NORMAL AND ABNORMAL REFRACTION. 

Emmetropia — Ametropia — Hypermetropia — Determination and Correc- 
tion of Hypermetropia — Myopia — Determination and Correction of 
Myopia — Astigmatism — Varieties of Astigmatism — Determination and 
Correction of Astigmatism — Anisometropia — Presbyopia — Correction of 
Presbyopia — Spectacles and their Adjustment 139-187 

CHAPTER V. 

DISEASES OF THE EYELIDS. 

Congenital Anomalies — Erythema of Lids — Erysipelas — Abscess of the 
Lid — Furuncle of the Lids — Hordeolum — Exanthematous Eruptions — 
Eczema of the Lids — Herpes Zoster Ophthalmicus — Blepharitis — 
Phthiriasis — Syphilis of the Lids — Tumors and Hypertrophies — Xan- 
thelasma — Chalazion — Sarcoma — Carcinoma — Lupus Vulgaris — Lepra 
— Elephantiasis Arabum — Tarsitis — Blepharospasm — Ptosis — Lagoph- 
thalmos — Symblepharon — Ankyloblepharon — Blepharophimosis — Tri- 
chiasis and Distichiasis — Entropion and Ectropion — Seborrhoea — Mil- 
ium — Molluscum Contagiosum — Ephidrosis — Chromidrosis — Sebaceous 
Cysts— Injuries 188-214 

CHAPTER VI. 

DISEASES OF THE CONJUNCTIVA. 

Congenital Anomalies — Hyperemia— Conjunctivitis (Ophthalmia) — Sim- 
ple or Catarrhal Conjunctivitis — Purulent Conjunctivitis — Conjuncti- 
vitis Neonatorum — Gonorrhceal Conjunctivitis — Croupous Conjunc- 
tivitis — Diphtheritic Conjunctivitis — Phlyctenular Conjunctivitis — 
Spring Conjunctivitis — Follicular Conjunctivitis — Granular Conjunc- 
tivitis (Trachoma) — Chronic Conjunctivitis — Lachrymal Conjunctivitis 
— Lithiasis Conjunctiva? — Toxic Conjunctivitis — Xerophthalmos — Amy- 
loid Disease of the Conjunctiva — Pterygium — Pinguecula — Abscess of 
the Conjunctiva — Ecchymosis — Chemosis — Emphysema — Lymphan- 
giectiasis — Syphilis — Tumors and Cysts — Lepra — Lupus — Tubercle — 
Pemphigus — Injuries — Affections of the Caruncle 215-258 



CONTENTS. 13 

CHAPTER VII. 

DISEASES OF THE CORNEA. 

PAGE 

Keratitis — Phlyctenular Keratitis — Ulcers of the Cornea — Results of Cor- 
neal Ulceration — Staphyloma — Xerotic Keratitis | Kerato-inalacia) — 
Neuro-paralytic Keratitis — Herpes Cornea? — Keratitis Bullosa — Vae 
lar Keratitis — Interstitial Keratitis — Keratitis Punctata — Keratitis Pro- 
funda — Keratitis Superricialis Punctata — Keratitis Marginalis — Riband- 
like Keratitis — Areas Senilis — Conical Cornea — Euphthalmos — Injuries 
— Foreign Bodies — Tumors — Congenital Anomalies — Filamentous Kera- 
titis — Blood-staining of the Cornea 2-39-209 

CHAPTER VIII. 

DISEASES OF THE SCLERA. 

Episcleritis — Scleritis — Sclero-kerato-iritis — Staphyloma — Abscess and 
Ulcers — Tumors — Injuries — Foreign Bodies — Congenital Pigmen- 
tation 300-307 

CHAPTER IX. 

DISEASES OF THE IRIS. 

Congenital Anomalies — Functional Motor Disorders — Hyperemia — Iritis 
— Simple Plastic Iritis — Syphilitic, Rheumatic, Gouty, Gonorrhceal, 
and Diabetic Iritis — Parenchymatous Iritis — Gummatous Iritis — 
Gumma of Iris — Purulent Iritis — Idiopathic Iritis — Traumatic Iritis — 
Sympathetic Iritis — Secondary Iritis — Serous Iritis — Chronic Iritis — 
Tumors — Tubercle — Sarcoma — Injuries — Anomalies of the Anterior 
Chamber 308-330 

CHAPTER X. 

DISEASES OF THE CILIARY BODY, AND SYMPATHETIC IRRITATION AND 
INFLAMMATION". 

Cyclitis — Plastic Cyclitis— Serous Cyclitis— Purulent Cyclitis — Injuries 
of the Ciliary Body — Tumors of the Ciliary Body — Irido-choroid- 
itis — Sympathetic Irritation — Sympathetic Inflammation (Ophthal- 
mitis) 331-342 

CHAPTER XL 

DISEASES OF THE CHOROID. 

Congenital Anomalies — Hyperemia — Choroiditis— Superficial, Deep, Dis- 
seminated, Central. Myopic, Suppurative Choroiditis flrido-choroiditis) 
and Unclassified Choroiditis — Panophthalmitis — Tumors (Sarcoma and 



14 CONTENTS. 

PAGE 

Carcinoma) — Tubercle — Injuries — Rupture — Hemorrhage — Detach- 
ment — Ossification — Atrophy of the Eyeball — Essential Phthisis Bulbi 
(Ophthalmo-malacia) 343-363 

CHAPTER XII. 

GLAUCOMA. 

Varieties of Glaucoma — Acute Glaucoma — Subacute Glaucoma — Chronic 
Glaucoma — Mechanism — Treatment — Secondary Glaucoma — Hemor- 
rhagic Glaucoma — Complicated Glaucoma 364-385 

CHAPTER XIII. 

DISEASES OF THE CRYSTALLINE LENS. 

Congenital Anomalies — Cataract — Senile Cataract — Juvenile or Congen- 
ital Cataract — Complicated or Secondary Cataract — Traumatic Cataract 
— After-cataract — Capsular Cataract — Capsulo-lenticular Cataract — 
Artificial Ripening — Extraction of Immature Cataract — Aphakia— 
Dislocation of the Crystalline Lens — Foreign Bodies in the Lens . 386-406 

CHAPTER XIV. 

DISEASES OF THE VITREOUS. 

Hyalitis — Purulent Inflammation— Pseudo-glioma — Opacities — Muscse — 
Hemorrhage — Synchisis — Synchisis Scintillans — Bloodvessel Forma- 
tion — Foreign Bodies — Entozoa — Detachment — Persistent Hyaloid 
Artery 407-415 

CHAPTER XV. 

DISEASES OF THE RETINA. 

Hypera?mia — Anaemia — Hyperesthesia — Anaesthesia — Retinitis — Serous, 
Parenchymatous, Syphilitic, Purulent, Hemorrhagic, Albuminuric, Dia- 
betic, Leucocytha?mic, Proliferating, Circinate, and Central Punctate 
Retinitis — Pigmentary Degeneration — Detachment — Hemorrhages — 
Changes in the Retinal Vessels — Aneurisms — Embolism of the Central 
Artery — Thrombosis of the Retinal Artery — Thrombosis of the Central 
Vein — Traumatisms — Retinal Changes from the Effect of Sunlight — 
Glioma — Cysticercus — Symmetrical Changes at the Macula Lutea in 
Infancy 416-455 

CHAPTER XVI. 

DISEASES OF THE OPTIC NERVE. 

Congenital Anomalies — Hyperemia — Anaemia — Intraocular Optic Neuri- 
ti- Papillitis; Choked Disc) — Atrophy of the Optic Nerve — Primary 
Atrophy — Secondary Atrophy — Consecutive Atrophy — Retinitic and 



CONTENTS. 1 5 

PAGE 

Choroiditic Atrophy — Orbital Optic Neuritis (Retrobulbar Neuritis; 
Toxic Amblyopia) — Injuries — Tumors — Hyaline Bodies (Drusenj in 
the Papilla 450-479 

CHAPTER XVII. 

AMBLYOPIA, AMAUROSIS, AND DISTURBANCES OF VISION WITHOUT OPH- 
THALMOSCOPIC CHANGES. 

Congenital Amblyopia — Congenital Amblyopia for Colors (Color-blind- 
3S — Reflex Amblyopia — Traumatic Amblyopia — Ursemic Amblyopia 
— Glycosuria Amblyopia — Malarial Amblyopia — Amblyopia from Loss 
of Blood — Amblyopia from the Abuse of Drugs — Hysterical Amblyopia 
— Pretended Amblyopia — Day-blindness — Night-blindness — Snow- 
blindness — Erythropsia — Micropsia — Megalopsia 480-489 

CHAPTER XVIII. 

AMBLYOPIA OF THE VISUAL FIELD, SCOTOMAS, AND HEMIANOPSIA. 

Partial Fugacious Amaurosis — Amblyopia of the Visual Field — Scotomas 
— Hemianopsia — Visual Tract — Significance of Hemianopsia — The 
Pupil in Hemianopsia 49U-499 

CHAPTER XIX. 

THE MOVEMENTS OF THE EYEBALLS AND THEIR ANOMALIES. 

Anatomy — Nerve-supply of the Muscles — Physiological Action of the 
Muscles — Rotation of the Eyeball around the Visual Line — Associated 
Movements — Binocular Vision — Overcoming Prisms — Field of Fixa- 
tion — Strabismus or Squint — Paralysis of the External Ocular Muscles 
— Varieties of Diplopia — Paralysis of the External Rectus — Paralysis 
of the Internal Rectus — Paralysis of the Superior Rectus — Paralysis of 
the Inferior Oblique — Paralysis of the Inferior Rectus — Paralysis of 
the Superior Oblique — Oculo-motor Paralysis — Method of Examination 
and Diagnosis of the Affected Eye — Ophthalmoplegia — Nuclear Ocular 
Paralysis — Associated Ocular Paralyses — Paralysis of the Internal Ocu- 
lar Muscles — Concomitant Squint — -Varieties and Causes of Concomitant 
Squint — Measurement of Squint — Treatment of Convergent Concomitant 
Squint — Treatment of Divergent Concomitant Squint — Spastic Strabis- 
mus — Insufficiency of the Ocular Muscles i Heterophoria) — Nystagmus 
— Monocular Diplopia 500-548 

CHAPTER XX. 

DISEASES OF THE LACHRYMAL APPARATUS. 

Dacryoadenitis — Hypertrophy of the Lachrymal Gland — Prolapse of the 
Lachrymal Gland — Fistula of the Lachrymal Gland — Syphilis of the 
Lachrymal Gland — Dacryops — Tumors of the Lachrymal Gland — 



16 CONTENTS. 

PAGE 

Anomalies of the Puncta Lachrynialia and Canaliculi — Anomalies of 
the Lachrymal Sac and Nasal Duct — Cause of Disease of the Lachrymal 
Sac and Nasal Duct — Character of the Lachrymal Secretion under 
Pathological Conditions 549-558 

CHAPTER XXL 

DISEASES OF THE ORBIT. 

Congenital Anomalies — Periostitis— Caries and Necrosis— Cellulitis — 
Inflammation of the Oculo-orbital Fascia — Thrombosis of the Cavernous 
Sinus— Tumors of the Orbit — Pulsating Exophthalmos — Exophthalmic 
Goitre — Affections or Diseases of the Adjacent Cavities — Injuries — Dis- 
location of the Eyeball— Enophthalmos 559-574 

CHAPTER XXII. 

OPERATIONS. 

Preparation of the Patient, Instruments, and Dressings— General and 
Local Anaesthesia— Infiltration Anesthesia— Epilation of the Eyelashes 
—Removal of a Meibomian Cyst— Operations for Ptosis— Tarsorrhaphy 
— Canthoplasty — Operations for Trichiasis — Operations for Entropion — 
Operations for Ectropion— Blepbaroplasty— Transplantation without a 
Pedicle— Thiersch's Method of Skin-grafting— Operations for Pterygium 
—Operations for Symblepharon— Transplantation of the Rabbit's Con- 
junctiva—Operations for Trachoma— Subconjunctival Injections of Ger- 
micides— Paracentesis Cornere — Application of the Actual Cautery— 
Saemisch's Section— Operations for Corneal Staphyloma— Tattooing the 
Cornea— Iridectomy— Iridotomy— Sclerotomy— Enucleation of the Eye- 
ball—Evisceration—Resection of the Optic Nerve— Extirpation of the 
Whole Contents of the Orbit— Operations for Cataract— Needle Ope- 
ration (Discission)— Suction Method— Linear Extraction— Extraction 
of Hard Cataract— Varieties of the Section— After-treatment and Acci- 
dents—Extraction without Iridectomy— Preliminary Iridectomy— Ope- 
rations for After-cataract (Secondary Cataract)— Operations upon the 
Eye Muscles— Complete and Partial Tenotomy— Advancement or Read- 
justment—Operations upon the Lachrymal Apparatus— Slitting the 
Canaliculus— Introduction of a Lachrymal Probe— Incision of a Stric- 
ture — Introduction of a Lachrymal Syringe— Excision of the Lachrymal 
Gland • 575-646 



APPENDIX. 



The Use of the Ophthalmometer— Rules for Measuring the Corneal Astig- 
matism with the Ophthalmometer— The Use of the Tropometer . 647-654 



DISEASES OF THE EYE. 



CHAPTER I. 

GENERAL OPTICAL PRINCIPLES. 

BY DR. JAMES WALLACE | REVISED BY DR. E. JACKSON. 

Refraction. — By refraction of light is meant the alteration 
which takes place in the direction of luminous rays, which pass 
obliquely from one medium into another of different density. 

A ray of light passing through air keeps the same direction 

Fig- 1. 




Refraction of light through a plate of glass bounded by plane surfaces which 
are parallel. A B is the incident ray, B C the same ray, refracted by the first 
surface, nearer to the perpendicular PP. CD the same ray, refracted by thesecond 
surface, becomes parallel to A B, its original direction. The ray H K, perpendi- 
cular to the surfaces B and C, undergoes no refraction. 

until it strikes obliquely the surface of a denser'medium, when 
its course is changed toward the perpendicular to that surface. 

i" Denser" and "rarer," thus used, do not denote specific gravity, but relative 
•ince to the transmission of light. The "denser" medium retards, the "rarer" 
accelerates it. 

2 (17) 



18 DISEASES OF THE EYE. 

If this denser medium is a piece of glass, bounded by parallel 
sides, the ray, as it passes through the second surface, is bent 
back again into the rarer medium. 

Rays passing from a denser into a rarer medium are deviated 
from the perpendicular. The ray now has a direction parallel to 
its original course ; the sides being parallel, the deviation at each 
surface is equal in extent, but opposite in direction. 

Fig. 2. 




Refraction through a denser medium having oblique surfaces. At each surface 
the ray is bent towards the base of the figure. 

If the denser medium is bounded by oblique surfaces, the 
deviation at the second surface does not restore the ray to its 
original direction ; but it still more increases the alteration. 

Index of Refraction. — The deviation of the ray from its course 
depends upon the difference in the density of the two media. 

A ray passing obliquely from one medium into another of the 
same density is not bent from its course. The relative resistance 
of a substance to the passage of light is expressed by its index of 
refraction. The absolute index of refraction is its resistance 
as compared with vacuum. As there is very little difference 
between the indices of refraction of air and vacuum, air is con- 
sidered as 1 for all calculations in lenses. Moreover, air is one 
of the media concerned in the relations of lenses to the eye. 

As the difference in the density of the two media increases, the 
ray is bent more sharply from its course, and the angle it forms with 
the perpendicular after refraction by a denser medium, is propor- 
tional >lv smaller than the angle formed by the ray before refraction. 

The angle formed by the ray with the perpendicular to the 



GENERAL OPTICAL PRINCIPLES 



19 



surface of the second medium is called the angle of incidt 
angle i. The angle formed by the ray with the perpendicular 
after refraction is called the angle of refraction, angle /•. The sine 



Fig. 3. 




E D sine of the ansrle of incidence. 
(Landolt.) 



G H sine of the ansrle of refraction. 



of the angle of incidence divided by the sine of the angle of re- 
fraction gives the index of refraction. The mode of calculating 
this is shown in the figure. 

An incident ray A B strikes the surface S S\ forming the angle of 
incidence A B P with the perpendicular PP. It is refracted at the 
surface S S . and passes into the second medium : but its course is now 
changed to the direction B Gr, nearer the perpendicular than before. 
The angle CB P i-? the angle of refraction. If. now, a circle is drawn 
around B, as a centre, and at the points D and G perpendiculars are 
drawn to the line P P . the line E D will be the sine of the angle of in- 
cidence, and the line G If will be the sine of the angle of refraction. 

ED 
The index of refraction is found by dividing E I) by G H, jt-tt = in- 
dex of refraction. In this case E D = 4, and G H = 3 {EB = G H). 
The index of refraction of the medium is % = 1.33 times that of air. 

It i- evident from this that the sines of the two angles are inversely 
proportional to the indices of refraction of their respective media. 

fr 11 = 3. E D =4. Iudex of tirst medium, air, = 1. Index of 
second medium =1.33. 

Gil: E I): : 1 : 1.33. 



20 



DISEASES OF THE EYE. 



The following table from Landolt contains the index of 
refraction of some of the principal substances. The index of 
refraction of the glass used in spectacles is about 1.53. 

Table of absolute indices of refraction from Landolt. 



I. SOLIDS 
Crown glass . 
Flint glass 

Ice .... 

Rock crystal . 
Quartz (ordinary index) 
Diamond 

Cornea .... 
Crystalline lens, cortical layer 

" " intermediate layer 

" " nucleus 



1.5 

1.57 to 1.58 

1.310 

1.562 

1.547 

2.48 to 2.75 

1.3365 

1.393 

1.419 

1.431 



II. LIQUIDS. 

Water 1.336 

White of egg 1.351 

Human blood ....... 1.354 

Sulphuric ether ....... 1.358 

Rectified alcohol ....... 1.372 

Canada balsam ....... 1.532 

Saturated solution of sea salt .... 1.575 

Bisulphide of carbon ...... 1.678 



III. GASES. 



Air 

Oxygen 
Nitrogen 
Carbonic acid 



1.000294 
1.000272 
1.000300 
1.000439 



Prisms. — In order to be refracted a ray of light must form 
an angle with the perpendicular to the surface of the medium of 
different density. Rays which strike the surface perpendicularly 
pass through without deviation. This is best understood by 
considering prisms. 

A prism is a portion of glass, or other transparent substance, 
included between two plane surfaces which are inclined to each 
other. The angle formed by the two surfaces is called the 
refracting angh of the prism, and is expressed in degrees. For- 
merly prisms were designated by the number of degrees in the 
refracting angle. 



GENERAL OPTICAL PRINCIPLES. 21 

Apex and Base of the Prism. — The sides converge to a thin 
edge at one extremity of the prism. This is called the apex. At 
the other extremity they diverge from each other forming the 
base. 

The position of a prism is described by the direction in which 
its base is situated ; thus, base up means that the prism is to be 
lxld in front of the eye, or ground into a spectacle glass, with 
the base or thickest part of the prism above ; in like manner the 
expressions base down, base in, or base out indicate that the base 
i- placed in one of these positions. 

Refraction Through a Prism. — A ray of light falling upon 
the surface of a prism is bent towards the perpendicular (Fig. 4). 

A glance at the figure shows that 
the perpendicular to the surface of a 
prism is inclined towards the base. 
The ray, therefore, is directed towards 
the base, and passing across the prism 
falls upon the surface of the air bound- 
ing it. The perpendicular is here di- 
rected away from the base, but the ray 
passing into air is deviated from the Deviation produced by a 

perpendicular, and consequeutlv ap- P nsm (Jackson). I, angle 
. .,, , , , * rr«i of incidence. R, angle of re- 

proaches still closer to the base. The fraction A angle of devia . 

refracted ray, therefore, is always de- tion. r-^-d = i. d equals 

viated towards the base of the prism. in weak P risms about * of B - 

To the eye of an observer placed at the other side of the 
prism the refracted ray seems to come from the direction of the 
apex, since a ray is projected backwards over the course given to 
it by its last refraction, and a single object appears double if 
with both eyes open a prism of sufficient strength is placed be- 
fore one of them. The angle which the ray in this last direction 
forms with the ray in its original direction is called the angle of 
deviation. 

When one eye on account of muscular weakness is unable to 
direct its visual line to the point of fixation, a prism will alter 
the direction of the ray from the point of fixation so that it coin- 
cides with the visual line of the weaker eye. The refractive 
properties of a prism are further utilized to test the strength of 




22 DISEASES OF THE EYE. 

the ocular muscles (see page 76) to neutralize the diplopia 
caused by abnormal deviation of the visual line, for example, 
in strabismus, and to detect malingerers who feign monocular 
blindness (see page 487). 

Angle of Deviation. — The angle of deviation is the angle 
formed by the incident ray with the refracted ray. The amount 
of this angle is nearly one-half of the refracting angle of the 
prism for all prisms between 1° and 10°. Above this the de- 
viation rapidly increases. 

When the angle of incidence, formed by a ray in the interior 
of a prism, amounts to 40° 49', the angle of refraction equals 
90° ; the angle of deviation, the difference between the two, then 
equals 49° 11'. The refraction which takes place at each sur- 
face of the prism must be considered in determining the amount 
of the deviation. When this is equal at the two surfaces the 
minimum amount of deviation is present. When the ray is 
perpendicular to one surface the angle of incidence, at the second 
surface, equals the angle of the prism ; and the deviation is greater 
in this case, as all the refraction takes place at one surface. A 
table of the minimum deviation of prisms is given on page 24. 

Limit-Angle of Refraction. — The greatest angle which a ray 
can form with the perpendicular is 90°. If the incident ray 
forms this angle, it can still enter the glass at an angle of 40° 49'. 
This is the limit-angle of refraction. 

In the same way rays in glass forming an angle of 40° 49' 
pass out into air, but if they form a greater angle than this, they 
are reflected back again into the glass and do not pass out. 
This phenomenon is called total refection (Fig. 5). 

Internal Reflection. — Rays may undergo a series of reflec- 
tions inside a prism until they finally strike the surface at 
such an angle that they pass out. A pair of prismatic spectacles 
in this way gives rise to a multiplication of images by means of 
rays which suffer internal reflection before they emerge from the 
lens. Thus they are projected in different positions from the 
object. 

Numbering of Prisms. — The designation of prisms by their 
angular deviation, instead of by their refracting angles, was urged 
by Dr. Edward Jackson, of Philadelphia, before the Ninth 



GENERAL OPTICAL PRINCIPLES. 23 

International Medical Congress. Two methods of accomplishing 
this have been proposed : — 

Fig. 5. 




The limit-angle of refraction (Landolt). The rays from the point L — LA, L B, 
L C, L D, L E — pass out of the denser medium with increasing angles of refrac- 
tion. L E, refracted as E E , parallel to the surface 8, forms the limit-angle for 
rays which still emerge. The ray L F\s reflected back to F . 

Dennett? 8 Method: The Centrad. — Dr. William S. Dennett's 
calculation has for its base an arc called the radian, whose length 
equals the radius of its curvature. Such an arc equals 57.295°. 
-V prism which will produce an angular deviation of the one- 
hundredth part of this arc is called one centred. The deviation 
of such a prism would therefore be .57295°. The merit of this 
method consists in the uniformity of the deviation, ten centrads 
having exactly ten times the deviation of one centrad. The 
deviations are so many hundredths of the radius measured on 
the arc. 

Prentice's Method: The Prism-Dioptre. — Mr. Charles F. Pren- 
tice proposes, as the standard of deviation, a prism which shall 
deflect a ray of light one centimetre at a plane one metre distant ; 
that is, the hundredth part of the radius measured on the tangent. 
This he calls the prism-dioptre. The value of the centrad and 
prism-dioptre will be given below. (See table.) 

There are two practical advantages connected with the method 



24 DISEASES OF THE EYE. 

of Mr. Prentice which also can be applied to the centrad. The 
prismatic deviation of a decentred lens may be very readily found, 
as Prentice has shown, by the following rule : If a lens be de- 
centred one centimetre, the prismatic deviation of the lens will be 
equal to as many prism-dioptres as the number of dioptres in the 
lens. Thus, if a 4-dioptre lens be decentred one centimetre, the 
prismatic deviation will be 4 prism-dioptres, or 4 centrads, since 
centrad and prism-dioptre almost exactly equal each other. The 
same lens decentred one- half centimetre would produce 2 prism- 
dioptres or centrads of deviation. 

The relation to the metre angle (page 54) is also very simple. 
One-half the interpupillary distance is the sine of the metre 
angle. The ratio of this to the point of fixation in hundredths 
gives nearly the number of prism-dioptres, or centrads of deviation, 
embraced in any number of metre angles. For example, if the 
interpupillary distance is 60 mm., one-half of this is 30 ; assuming 
the amount of convergence to be 4 metre angles, 25 centimetres, 
or 250 mm., is the distance of the point of fixation. The devi- 
ation of the visual line then is 30 in 250, or 12 in 100 =12 
centrads, or 12 P. D. For small arcs the tangent and the sine 
agree very closely with the arc. Four metre angles of con- 
vergence then represent 12 centrads of deviation, or 12 prism- 
dioptres. 



able of 

Centrads. 
1 


relative values of cer, 

Prisiu-diopti 

1 

2.0001 

3.0013 

4.0028 

5.0045 

6.0063 

7.0115 

8.0172 

9.0244 

10.0333 

15.114 

20.270 

42.288 


'.trads and 

es. 


prism-dioptres. 

Refracting angle of 
prism required. 
. . 1.06° 


2 




. . 2.16 


3 
4 




3.24 
. . 4.32 


5 




. . 5.40 


6 




. . 6.47 


7 




. . 7.54 


8 




. . 8.62 


9 




. . 9.68 


10 




. . 10.73 


15 




. . 16.1 


20 
40 




. . 21.13 
. . 39.0073 



The prisms represent the minimum deviation with an index of refraction of 
1.53. 




GENERAL OPTICAL PRINCIPLES. 25 

Rays of Light. — Any luminous point diffuses light in all 
directions in straight lines called rays. As the rays proceed 
from the luminous source those 
which diverge from one another 
become more widely separated. 
(Fig. 6.) 

If a circular aperture one centi- 
metre in diameter be made in a 
metal plate, and a luminous point 
be placed at different distances from 
it, for example, at one metre and at 
ten metres, the rays coming from 
ten metres, which pass through the 
aperture, will be less diverging than 
those which come from one metre. Divergence oi rays from a luminous 
A cone of light will pass through source (Loring). 

the aperture in each case, but the 

shape of it will be different according to the distance of the 
light from the aperture in the screen. When the round hole, 
1 centimetre in diameter, is 1 metre distant from the point of 
light, the cone has a base 1 centimetre in diameter, and the apex 
is situated in the luminous point 100 centimetres distant. The 
rays have diverged 1 centimetre in travelling 100 ; the metal 
plate has cut off all other rays having a greater divergence. If 
the cone of light passes through the aperture and falls upon a 
distant wall, the cone will preserve the same proportions, viz., 
the base will be T ^ 7 of the altitude. If the wall be 5 times the 
distance of the screen from the light, a luminous circle 5 centimetres 
in diameter will be formed upon the wall. If, now, the light is 
removed to a point 10 metres from the screen (1000 centimetres), 
a cone of light is formed whose base is 1 centimetre and whose 
altitude is 1000. The rays which pass through the aperture 
have now only -fa of the divergence of the rays in the former 
case ; the base of the cone is y^Vo of the altitude. The cone of 
light will now form a circle on the wall 5 metres beyond the 
aperture, only 1.5 centimetres in diameter. If the point of light 
be at a very great distance, there will be no difference in the size 
of the luminous circle and the aperture in the screen ; the size 



26 DISEASES OF THE EYE. 

of the circle remains about 1 centimetre on the wall at 5 metres 
from the screen. The rays, therefore, have a nearly parallel 
direction. This is shown in Fig. 7. 

Fig. 7. 




Rays diverging from the candle A pass through the aperture in the screen S, 
and form the cone of light whose base is the distance a a'. Rays from a more 
distant candle B, having a greater divergence than b b , are intercepted by the 
screen S. 

Rays which enter the pupil of the eye from a point 6 metres 
distant have so little divergence that they may be considered par- 
allel. The average size of the pupil being 4 mm., the divergence 
is only -g-^oo- All rays diverging more widely than this are 
excluded by this width of the pupil. 

There is very little difference to the eye between rays 
diversrine from 6 metres and those coming from an infinite dis- 
tance, but for lenses of long focal distance and large aperture 
an infinite distance is required in order to obtain parallel rays. 
The sun and stars are so remote that the rays coming from 
them have no appreciable divergence, and they are considered 
parallel. 

Fig. 8. 



Showing how distant rays become parallel (Loring). 

Parallel Rays. — Parallel rays are brought together by a lens 
at its principal focus; conversely, rays which diverge from the 
principal focus of a lens are parallel to one another after being 
refracted by the lens. As parallel rays must emanate from a 
distant object, any eye which brings parallel rays to a focus is 



GENERAL OPTICAL PRINCIPLES. 27 

adapted for distant vision, and if its accommodation is relaxed 
is emmetropic. When light passes from such an eye from within 
outwards the rays arc parallel. 

Divergent Rays. — Kays which diverge from one another require 

more refraction to bring- them together at the same distance behind 
a lens, than rays which are parallel ; consequently, divergent rays 
are brought together at a farther point than the principal focus. 
The nearer the point of divergence lies to the lens, the farther 
away from the lens is the point where the rays converge to a focus. 

Convergent Rays. — Only those rays converge to a common 
point which have passed through a convex lens, or have been 
reflected from a concave mirror. 

Significance of the Different Rays. — The refraction of the 
eye is determined by the character which the rays must have in 
order to be brought to a focus on the retina. 

An emmetropic eye, with relaxed accommodation, requires rays 
to be parallel in order that they shall meet on the retina. 

A myopic eye requires the rays to diverge from some near point 
in order to meet on its retina. 

A hypermetropic eye requires rays which already have conver- 
gence to some point in order to unite them on its retina. 

An emmetropic eye emits parallel rays. 

A myopic eye emits convergent rays. 

A hypermetropic eye emits divergent rays. 

Lenses. — A lens is a portion of glass, or other transparent 
substance, bounded by two curved surfaces, or by one curved 
surface and one plane surface. The curved surfaces are convex, 
elevated in the centre and thin at the edge ; and the concave, 
hollowed out in the centre and thick at the edge. 

A lens may be regarded as a series of prisms with the refracting 
angles increasing in value from the centre toward the periphery. 

In a convex lens the bases are directed towards the centre of the 
lens, and rays, therefore, are refracted towards the axis which 
passes through the centre. In a concave lens the bases of the 
prisms are directed away from the centre, and rays, therefore, are 
refracted away from the axis. As the angles increase from the 
centre outwards, the peripheral rays will be refracted more than 
the central ravs. The result of this is that in a convex lens the 



28 



DISEASES OF THE EYE. 



rays after refraction converge to the same point, the increased 
bending of the more peripheral rays just sufficing to compensate 
for their greater distance from the axis. In a concave lens the 



Fig. 9. 




Lenses as prisms. 

rays diverge more widely as they pass through the peripheral 
parts of the lens, with the result of making them appear to have 
diverged from a common point. 

Focus of a Convex Lens. — The point to which rays converge 
after refraction by a convex lens is called its focus. 

Principal Focus of a Convex Lens. — The principal focus of a 
lens is the focus for parallel rays. As the most distant rays are 

Fig. 10. 




Principal focus of a convex lens. The parallel rays, a, i, c, d, are refracted by 
the lens so as to unite at the point F on the axis P\ the ray P undergoes no 
refraction. F is the principal focus. 



GENERAL, OPTICAL PRINCIPLES. 



29 



only parallel, never convergent, the principal focus is the shortest 
locus, unless the lens be combined with another convex lens, or 
concave mirror. Rays diverging from the principal focus of a 
lens are rendered parallel after passing through the lens, and 
come to a focus at an infinite distance. 

Conjugate Focus of a Convex Lens. — When rays diverge 
from any point nearer than infinity, they are brought together 
at a point on the other side of the lens farther than the principal 
focus. The point from which rays diverge and the point to 
which they converge are called conjugate foci. As the point of 
divergence approaches the lens the point of convergence recedes ; 
when the point of divergence is at twice the focal distance of the 
lens, the point of convergence is at an equal distance on the other 
side. The conjugate foci are now equal. 

As the point of divergence approaches still closer, the point of 
convergence is at a greater distance, until when the point from 
which the rays diverge is at the principal focus the rays converge 
at an infinite distance. 

Fig. ll. 




Conjugate focus of a convex lens. The two dots in the axis represent the 
principal foci, one being marked F. Rays diverging from converge after refrac- 
tion to the point F , farther than the principal focus. Rays from F 1 also converge 
after refraction to 0. and F' are conjugate foci. 



Rays diverging from either of these points converge towards 
the other. When rays diverge from a point whose distance is 
equal to, or greater than, the principal focus, the conjugate focus 
is positive. When the distance is less than the principal focus, 
the conjugate focus is negative. 

Virtual Focus of a Convex Lens. — When rays diverge from 
some point nearer to a lens than its principal focus, the rays 



30 



DISEASES OF THE EYE. 



after refraction still continue divergent. These divergent rays, 
if traced backwards, would meet in a point on the same side of 
the lens from which they diverged. This point is called a nega- 
tive, or virtual focus, because the rays do not really meet here, 
but are given a direction by the lens as if they had diverged 

Fig. 12. 




Virtual focus ot a convex lens. Rays from the point 0, less than the principal 
focal distance, diverge after refraction as if they came from the point V. V is the 
virtual focus of 0. 

from this point. (Fig. 12.) Therefore, the point from which 
rays diverge, and the point to which they converge, are focal 
points. 

Foci of Concave Lenses. — The foci of concave lenses for 

Fig. 13. 




Principal focus of a concave lens. Parallel rays a, b, d, e, after refraction by 
the concave lens L, are rendered divergent as if they came from the point F on the 
axis c. The ray c is not refracted. F, the principal focus of a concave lens, is 
virtual. 

parallel or divergent rays are virtual, or negative. They are the 
points from which the rays seem to diverge after passing through 
the lens. 



GENERAL OPTICAL PRINCIPLES. 31 

Principal Focus of a Concave Lens. — When parallel rays 
fall upon a concave lens they are rendered divergent. If these 
rays be traced backwards, they will seem to have diverged from 
a point near the lens. This point is the principal focus. (Fig. 
13.) 

Conjugate Foci of Concave Lenses are also virtual, and found 
in a similar manner. 

Formation of Images by a Lens : Optical Centre. — In the 
lens (Fig. 14) the point on the axis is called the optical centre. 

Fig. 14. 




0. Optical centre of lens (Landolt). The point C" is the centre of curvature 
for the surface S". The point C is the centre of curvature for the surface .S". A 
ray passing from C" to C" would be perpendicular to both surfaces. It would 
pass through without deviation. This ray is called the axial ray, or axis. 

The radii C" .7", and C J 1 , being parallel, a ray in the lens passing in the 
direction -T J" must form equal angles at the two surfaces. The point where 
this ray intersects the axis is the optical centre. 

Any ray passing through this point is refracted equally at both 
surfaces, since it forms equal angles with the radii of the two 
surfaces. The direction of the ray is therefore the same after 
refraction by the second surface as it was before refraction by 
the first. For thin lenses it may be said that any ray directed 
to the optical centre passes through without deviation. These 
rays are called secondary axes. 



32 



DISEASES OF THE EYE. 



The ray drawn from any point in an object to the optical centre 
of a lens gives the line on which the image of the point is to be 
found. A ray from the same point in the object, passing paral- 
lel to the axis of the lens, would be refracted through the princi- 
pal focus of the lens, since the principal focus is the focus for 
parallel rays. (Fig. 15.) 

Fig. 15. 




Position and size of image formed by convex lens (Landolt).— The ray A, K', 
from the point A, being directed to the optical centre of the lens, continues its 
course in a parallel direction K' A." Another ray passing from A, parallel to the 
axis L' L' ,is refracted through p",the principal focus, and, intersecting the ray 
A K" A" , determines the position of the image of the point A. Still another 
ray passing from A through the anterior principal focus 9', after refraction, is 
parallel with the axis L' L", and meets the other rays in the point A." 

In order to find the position and size of an image formed by 
a lens, it is only necessary to draw two lines from each extremity 
of the object : one passes through the optical centre of the lens ; 
and the other, parallel with the axis of the lens, would be re- 
fracted to the principal focus. The position of the image is found 
at the points where these lines intersect. 

The size of the image is proportional to the size of the object, 
as the distance of the image from the optical centre is to the dis- 
tance of the object from the optical centre. When the object is 
situated at a greater distance from the lens than its principal 
focus, the image is a real, inverted one. 

In the figure (Fig. 16), B is the object ; the rays diverging 



GENERAL OPTICAL PRINCIPLES. 33 

from intersect in 0', which is the position of the image of the 
point 0. Similarly the rays from B unite in B', the position of 
the image of the point B; B' (J' is the image of OB. 

Fig. 16. 




Image formed by a convex lens. B is the object ; 0' B' is the inverted 
image. 

When the object is situated nearer to the lens than its princi- 
pal focus, the image is a virtual, erect one. 

The virtual image of a convex lens appears to be at the point 
from which the rays refracted by the lens seem to have diverged. 

Fig. 17. 




Virtual image of a convex lens. C D is the object ; C U is the virtual image, 
erect and magnified. 

(Fig. 17.) From the point C, of the object CD, the ray CS is 
parallel to the axis. It therefore is refracted to the principal 
focus, P. The ray C passes through unchanged. By project- 
ing these rays backwards they meet in C f , the image of the point 
3 



34 DISEASES OF THE EYE. 

C. The rays from the point D seem to have diverged from D'. 
An enlarged, erect image is thus formed in C D'. 

The image formed by a concave lens is mostly virtual and dimin- 
ished. Two rays proceeding from a point 0, in the object, one 

Fig. 18. 




Virtual image of a concave lens. 0' B' is the virtual image of the candle, B, 
erect and diminished in size. 

parallel to the axis, which seems after refraction to have diverged 
from the principal focus, and is traced backwards, and the other, 
which is directed to the optical centre, at their intersection, de- 
note the position of this point in the image. (Fig. 18.) 

Focal Distance of a Lens. — The distance from the optical 
centre of a lens to the focal point is called the focal distance. 

The length of this depends upon the radii of curvature of the 
surfaces of the lens, and on its index of refraction. Representing 
the radius by r, the index of refraction of the lens by n, that of air 

being 1, F = ., is the formula for obtaining the focus of a 

Zi{ n — i ) 

bispherical convex or concave lens. The formula for a piano- 
spherical lens is F = > as the refraction is effected at one 

1 n — 1 

surface. The mode of obtaining this is given below. 1 (Fig. 19.) 

1 I. In the plano-convex lens L, the surface D being perpendicular to the 
incident ray, no refraction takes place. S is the convex surface, C I is 
the radius of curvature, r. R I is the incident ray, I F is the refracted 
ray, R I C is the angle of incidence, II I F is the angle of refraction, equal 
to H I P + P 1 r F. HI P=R I C. 

PI F, the ang. of deviation, = H I F— II I P. 

Angle of deviation = ang. of refraction — ang. of incid. 

II. If e e / = sine of the ang. of incidence, then g <f = sine of the ang. of 



GENERAL OPTICAL PRINCIPLES. 



35 



Numeration of Lenses. — The refractive power of a lens is 
the inverse of its focal distance. If the refractive power of a 

refraction (the radii / e and / </' being equal), e e' is inversely proportional 
to g if , as the index of refraction of the lens is to that of air. (See page 19.) 
Representing the index of the lens as n, that of air being 1, we have 
e e' : g g' : : 1 : n. 

Fig. 19. 




The angles R I C and /// F, being small, are proportional to their sines. 

R IC : H I F : : e e' : g g' ; or, substituting, R I C : H I F : : 1 : n. 

n(RIC) = II I F. 

URIC=\, H I F—n. 

III. Ang. of refraction = /(. 

Ang. of incid. = 1. 

Ang. of deviation = ang. of refrac. — ang. of incid. = » — 1. 

In the two triangles, SCI and S F I, the angle I C S = R I C, ang. of 
incid. The angle I F S= P I F, angle of deviation. The side / S being 
common, the angles are inversely proportional to the bases of their respective 
triangles. 

IC S: IFS : : F S : C S. F S nearly equals F I. 

I C S = ang. of incid. = 1. (II.) 

I FS= ang. of deviation = n — 1. (III.) 

F S= focus F. C S = radius r. 

1 : n — 1 : : F : r. 

F= 



»—l 

The focus of a piano-spherical lens is equal to the radius of curvature, 
divided by the index of refraction — 1. 

In a bi-spherical lens the ray is refracted at each surface ; if the radii of 
curvature are equal, the refraction is the same at each surface, or double that 
of a piano-spherical lens. The focus will consequently be one-half that of a 



piano-spherical lens. /' = 



2(„-l) 



i Wallace.) 



36 DISEASES OF THE EYE. 

lens whose focal distance is one metre is represented by 1, then a 
lens whose focal distance is two metres has only one-half the re- 
fractive power of the first, since the rays are not bent so sharply 
by the second lens. Again, if a lens bends rays so sharply that 
they meet the axis at one-half metre's distance, its refractive 
power is twice that of a lens of one metre focus. 

The focus of a bi-convex lens (with equal radii), made of glass 
with an index of 1.50, has the same length as the radius of cur- 
vature. 

V T 

= 2(n — 1) = 2(1.50 — 1) 
F = r. 

Glass used in spectacle lenses has an index of 1.53, conse- 
quently — 

F=^- 
1.06 

r = 1.06 F. 

In the old system the lenses were marked according to their 
radii of curvature in Paris inches, and the focal distance was 
somewhat less than the radius of curvature. As all the lenses 
in use had longer focal distances than 1 inch, they were fractions 
of the refractive power of a lens of 1 inch focus, viz., J, \, |, -Jg-, 
etc. 

In 1867 Nagel proposed to number lenses by their refractive 
power. By adopting as a standard a lens of longer focal dis- 
tance than one inch, viz., one metre (40 inches), the greater num- 
ber of lenses are made multiples of refractive power of the 
standard, and are based on their focal lengths in metres and 
fractions of a metre, instead of being based on their radii of 
curvature. 

The term dioptre was proposed by Monoyer for a lens of 1 
metre focus. A lens of 2 metres focus is only J the refractive 
power, or 0.50 D. The present scale of lenses comprises a series 
from 0.1 2 I) to 22 D. Between 0.1 2 D and 1 .25 D the lenses have 
an interval of 0.12 D. From 1.25 D to 5 D the interval is 0.25 
D, from 5 to 8 D an interval of 0.50 D, from 8 to 18 D an inter- 
val of 1 D, and from 18 to 22 D the interval is 2 D. This uni- 
formity in the intervals between the lenses is an important 



GENERAL OPTICAL PRINCIPLES. 



37 



advantage over the old system, in which the lack <>f uniformity in 
this respect was a conspicuous feature. 

To find the focal length of any lens in the dioptric system 
divide one metre, or 100 centimetres, by the number of dioptres: 

thus, the focal length of a lens of 5 D is — = 20 cm. 
& 5 





No. of lens 


Focal distance 


1 ocal distance in 


Nearest corre- 




in dioptres: 


iu millimetres. 


English inches. 


sponding lens in 
old system. 




- 


0.12 


8000 


314.96 








0.25 


4000 


157.48 


144 






0.37 


2666 


104.99 








0.50 


2000 


78.74 


72 


Interval of 




0.62 


1600 


62.99 


60 


0.12 D. ' 




0.75 


1333 


52.5 


48 






0.87 


1143 


44.99 


42 






1 


1000 


39.37 


36 






1.12 


-- 


34.99 








1.25 


800 


31.5 


30 




' 


1.50 


666 


26.22 


24 






1.75 


571 


22.48 








2 


500 


19.69 


20 






2.25 


444 


17.48 


18 






2.50 


400 


15.75 


16 






2.75 


363 


14.31 


15 or 14 


Interval of 
0.25 D. 




3 

3.25 

3.50 


333 

308 
285 


13.12 
12.11 
11.25 


13 
12 
11 






3.75 


267 


10.49 


10 






4 


250 


9.84 


9 






4.25 


235 


9.26 








4.50 


222 


8.74 


8 






4.75 


210 


8.29 








5 


200 


7.87 






: 


5.50 


182 


7.16 


7 






6 


166 


6.54 




Interval of 




6.50 


154 


6.06 


6 


0.50 D. 




7 


143 


5.63 


5 






7.50 


133 


5.25 








8 


125 


4.92 






: 


9 


111 


4.37 


4.5 






10 


100 


3.94 


4 






11 


91 


3.58 


3.5 






12 


83 


3.27 


3.25 


Interval of 




13 


77 


3.03 


3. 


ID. " 




14 


71 


2.8 


2.75 






15 


66 


2.64 








16 


62 


2.44 


2.5 






17 


59 


2.32 


2.25 






18 


55 


2.17 




Interval of 
2D. 1 


' 


20 


50 


1.97 


2. 


. 


22 


45 


1.79 





38 



DISEASES OF THE EYE. 



In the old system, the lenses are ground with a radius of cur- 
vature in Paris inches. The focal length is almost exactly the 
same in English inches as the radius of curvature is in. French 
inches. The English inch = 25.4 mm.; the French inch= 27.07 
mm.; 25.4 X 1.06 = 26.92. 

In column 3 of the table, the focus is given in English inches, 
as it is customary to compare the French lenses with the dioptres 
by their focal length in English inches. A lens of 1 dioptre has 
a focal length of 39.37 English inches. There is no lens in the 
old system which corresponds to it exactly. The nearest equiva- 
lent would be a lens of 40 inches. 

The lenses used for spectacles are spherical and cylindrical. 

Spherical Lenses. — A spherical lens is represented by a section 
of a sphere, or of two sections of a sphere placed together by 

Fig. 20. 




1. Biconvex lens. 2. Plano-convex lens. 3. Concavo-convex lens, convergent 
meniscus. 4. Biconcave lens. 5. Plano-concave lens. 6. Convexo-concave lens, 
divergent meniscus. 

their plane surfaces. Light passing through a spherical lens is 
refracted equally in all planes. 



GENERAL OPTICAL PRINCIPLES. 39 

Cylindrical Lenses. — A cylindrical lens is a section of a cylin- 
der parallel to its axis. Light passing through a cylindrical lens 
is oot refracted in a 'plane parallel to its axis. But in a plane 
perpendicular to the axis, rays are rendered convergent or diver- 
gent, according as the cylinder is convex or concave. 

Convex lenses are designated + ; concave lenses — . 

Combination of Lenses. — If two or more lenses are placed 
together, say + 2 dioptres -f 3 dioptres and + 4 dioptres, 
the combination forms a dioptric power equal to their sum, viz., 
9 dioptres ; such a combination has, with thin lenses, a focal 
distance of ^ = 11 centimetres. If these lenses are placed at 
their focal distance from an object, the rays coming from the 
object, after passing through the lenses, are parallel. 

Two or more concave lenses placed together likewise produce 
a dioptric effect equal to their sum. 

Combination of Convex and Concave Lenses. — If a concave 
lens and convex lens of equal strength be placed together, they 
will neutralize each other so exactly that a distant object viewed 
through them will appear neither enlarged nor diminished, and 
there will be no prismatic deviation on gently shaking the lenses 
in a direction parallel to the surface. 

Should they be unequal, on shaking them, an object (the edge 
of a wall or window frame is suitable) will be displaced towards 
the centre of the lens, if the concave is stronger, and away from 
the centre, if the convex is stronger. The value of the combi- 
nation will be the difference between the strength of the two. 
For instance, a + 3 dioptre and a — 2 dioptre equal -f- 1 dioptre ; 
a + 2 dioptre and — 4 dioptre = — 2 dioptre. 

A — 2 dioptre lens gives to parallel rays a direction as if they 
came from a point 50 centimetres away. Conversely, we may 
represent rays diverging from any near point by the concave 
lens whose principal focus equals that distance. Let rays, for 
example, diverge from a point 15 centimetres away; they evi- 
dently are similar to parallel rays which have passed through a 
concave lens of 15 centimetres focal distance, ^ = 6.66 dioptres. 

If we wish to find the conjugate focal distance of any lens for 
rays which diverge from 15 cm., we subtract 6.66 from the diop- 
tric power of the lens ; the remainder gives a lens whose focal 



40 DISEASES OF THE EYE. 

distance would be the conjugate desired. If we wish to find the 
conjugate focal distance of a 12 dioptre lens for rays which 
diverge from 15 cm., we subtract 6.66 from 12 = 5.33 dioptres; 
18.8 cm. is the conjugate focal distance. 

Combination of Cylindrical Lenses with Spherical Lenses. — 
A cylindrical lens is curved only in the direction perpendicular to 
its axis ; rays which enter the lens are refracted in this plane to 
the focus of the lens exactly as in the case of a spherical lens. 

In the opposite direction, that is parallel to its axis, the surface 
of a cylindrical lens is flat; rays entering are not refracted in 
this plane, but pass through unchanged. The effect of a cylin- 
drical lens placed in front of the eye is to increase or diminish 
its refraction in the direction at right angles to its axis, but in 
the opposite direction the refractive power is unchanged. 

A convex 4-dioptre cylindrical lens, with its axis in a vertical 
direction (written + 4 D cyl., axis 90°), increases the refraction 
in the horizontal direction 4 dioptres, but does not alter the re- 
fraction in the vertical direction. The horizontal plane is ex- 
pressed by the term horizontal meridian; the vertical plane by 
the term vertical meridian. 

A concave cylindrical lens of 4 dioptres, with its axis horizontal, 
(written — 4 D cyl., axis 180°) diminishes the refraction of the 
vertical meridian 4 dioptres, but does not affect the refraction of 
the horizontal meridian. 

A convex lens of 3 dioptres, combined with a convex cylin- 
drical lens of 2 dioptres, with its axis vertical (written + 3 D 3 
-|- 2 D cyl., axis 90°), adds to the horizontal meridian + 5 
dioptres, but to the vertical meridian only 3 dioptres. 

The combination of a convex spherical lens with a concave 
cylindrical lens has the following effect: In the direction parallel 
to the axis of the cylinder the combination equals the full refrac- 
tion of the spherical ; in the direction at right angles to the axis 
of the cylinder the refraction is equal to the difference between 
the two lenses. If the convex spherical is stronger than the con- 
cave cylinder, the difference is still represented by a convex glass. 
For example, + 2 D sph., 3 — 1.50 D cyl., axis 180° = + 0.50 
D sph., 3 + 1-50 D cyl., axis 90°, because + 2 D in the meri- 
dian of 180° is not diminished, but in the meridian of 90° it is 



GENERAL OPTICAL PRINCIPLES. 41 

reduced to 4- 0.50 D. Now, 4- 0.50 D sph. produces this amount 
of iv tract i ci i at 90°, and supplies 4- 0.50 I) of the requisite 4- 2 
Dat 180°, leaving 4- 1.50 D to be supplemented by a cylindrical 
lens with its axis at 90°. 

In place of writing 4- 2 D sph., C —1-50 D cyl., axis 180°, 
a more simple expression Mould be + 0.50 D sph., 3 + 1*50 
I) cyl., axis 90°. 

When, however, the concave cylindrical lens is stronger than 
the convex spherical the difference is represented by a concave 
lens, thus + 3 D sph., 3 — 6.50 D cyl., axis 180°, signifies in the 
horizontal meridian convex 3 D, and in the vertical meridian 
concave 3.50 D. It is necessary to combine a convex with a 
concave lens in order to obtain this effect. The refractive power 
of this combination can be expressed in three different ways : — 
4- 3 D sph., C — 6.50 D cyl., axis 180°. 
— 3.50 D sph., C 4- 6.50 D cyl., axis 90°. 
4- 3 D cyl., axis 90° C — 3.50 D cyl., axis 180°. 

In the first combination +3D sph. gives the 4- 3 D neces- 
sary for the horizontal meridian, but increases the refraction of 
the vertical meridian 3 D instead of diminishing it ; therefore the 
— 6.50 D cyl., axis 180°, expends 3 D of its refractive power in 
neutralizing the effect of the + 3 D sph., and with the remainder 
diminishes the refraction of the vertical meridian 3.50 D. 

In the second combination, — 3.50 D sph., 3 + 6.50 D cyl., 
axis 90°, the concave spherical lens diminishes the refraction of 
the vertical meridian 3.50 D, but also diminishes the refraction 
of the horizontal meridian 3.50 D ; as this already requires 4- 3 D, 
we must add 4- 3.50 D more to compensate for the concave spheri- 
cal, making 4- 6.50 cyl., axis 90°. 

In the third combination, 4- 3 D cyl.. axis 90° 3 — 3.50 D 
cyl., axis 180°, 4- 3 D cyl., axis 90°, increases the refraction of the 
horizontal meridian without altering the refraction of the vertical 
meridian, and the — 3.50 D cyl., axis 180°, diminishes the re- 
fraction of the vertical meridian without affecting the refraction 
of the horizontal. 

With the combination of a convex spherical and cylindrical 
lens, e.g., 4- 3 D sph., 3 4- 2 D cyl., axis 90°, a concave 0.50 D 
cylinder with its axis at right angles to the axis of the convex 



42 



DISEASES OF THE EYE. 



cylinder, in this case at 180°, diminishes the refraction of the 
vertical meridian 0.50 D, the combination then equals -f 2.50 D 
in the vertical meridian and + 5 D in the horizontal = + 2.50 
D sph., C + 2.50 D cyl., axis 90°. 

A convex cylinder + 0.50 D added to the same combination, 
with its axis at right angles to the axis of the first cylinder, that 
is, + 0.50 D cyl., axis 180° with +3D sph., 3 + 2 D cyl., axis 
90°, increases the refraction in the vertical meridian + 0.50 D. 
The combination then equals -4- 3.50 I) in the vertical meridian, 
+ 5D in the horizontal. This is obtained by + 3.50 D sph., 
C + 1-50 D cyl., axis 90°. 

Visual Angle. — The apparent size of an object depends upon 
the size of the visual angle. 

The visual angle is the angle formed by the lines drawn from 
the two extremities of an object to the nodal point of the eye. 
The nodal point of the eye is analogous to the optical centre of a 
lens. It is situated 15 mm. in front of the retina, and 7 mm. 
behind the cornea. Rays directed to this point pass through 
without deviation. 

As the rays directed to the nodal point of the eye are not re- 
fracted, but continue the same course until they strike the retina, 
if lines are drawn from the extremities of an object through the 
nodal point of the eye, and continued until they fall upon the 
retina, the size of the retinal image of the object is obtained. 

The figure shows that the object, in order to subtend the same 

Fig. 21. 




The Visual Angle. 



angle, must be larger the farther it is removed from the eye. 
The letter A, seen clearly at 6 metres, would have to be three 
times as large in order to be seen distinctly at 18 metres, and 



GENERAL OPTICAL PRINCIPLES. 43 

ten times as large in order to be seen clearly at GO metres. The 
visual angle in the three cases remains the same. 

Visual Angle in Emmetropia. — In the emmetropic eve the 
nodal point is situated 7 mm. behind the cornea, and 15 mm. in 
front of the retina. The size of the retinal image is, to the size 
of the object, as the distance from the retina to the nodal point 
(15 mm.) is t<> the distance from the nodal point to the object. 
Therefore, if an object is situated at 1 metre distance (1000 mm.), 
its image will be yu^ir of the size of the object. 

Retinal Image in Ametropia. — In hypermetropia, the axis of 
the eye being shorter, the retina is situated nearer the nodal point ; 
the image is therefore smaller : while in myopia, with an increase 
in the axis of the eye, the retinal image is larger. 

Visual Acuteness; Limit of Perception. — An object one 
centimetre in size placed one metre distant from an emmetropic 
eye (that is, an eye without any error of refraction), which is 
normal in other respects, is plainly visible. If this object is moved 
farther and farther away, it forms a progressively smaller visual 
angle, until a point is reached beyond which it cannot be per- 
ceived, owing to the diminutive size of the visual angle. The 
limit of perception has now been reached. 

The angle which the object subtends, at this distance from the 
eye, represents the maximum acuteness of vision. An object twice 
the size would be seen distinctly at twice this distance. An 
object one-half the size could not be distinctly seen at more than 
half this distance. In general, the size of the object denoting the 
acuteness of vision is always proportional to the distance. 

Normal Acuteness of Vision. — Snellen determined the normal 
acuteness of vision to be the power of distinguishing letters sub- 
tending an angle of 5'. These letters were formed of strokes whose 
width was \ the size of each letter; consequently, they were seen 
under an angle of only V. The openings in the letters and the 
spaces between contiguous strokes, as nearly as possible, were 
made to conform to the same angle. 

The relation of the size of the letter to the distance at which it 
should be discerned by a normal eye is expressed by the tangent 
of the angle of 5' = .001454. The size of a letter, the percep- 
tion of which constitutes normal vision at a given distance, may 



44 DISEASES OF THE EYE. 

be obtained by multiplying the distance by .001454. At the 
distance of one metre the size of this standard letter is 1.45 mm. 
(.001454 X 1000 mm.). At a distance of six metres the size of 
the letter required is 8.7 mm. (1.45 x 6). The size of the retinal 
image of a standard letter of six metres = qI^q °f 8.7 = .02175 
mm., and the strokes, or openings, being ^ the size, have an image 
of .00435 mm. A large number of people, after correction of their 
ametropia, have a visual acuity of 1.25 of normal, and therefore 
letters, constructed on an angle of 4', have been used for testing 
visual acuity. The retinal images of the strokes of such letters are 
f of .00435 = .00349 mm. The size of the cones of the macular 
region varies from .0033 mm. to .0036 mm., showing a most inte- 
resting relation between the limit of perception and the anatomical 
structure of the retina. 

ACCOMMODATION. 

Rays from a nearer source are focused by a convex lens at a 
greater distance. But the eye being inexteusible, the adaptation 
for different distances is not effected by increasing the length of 
its axis, but by increasing the refractive power of the lens. The 
rays diverging from near objects are thus brought to a focus at 
the same distance as the rays diverging from remote objects. The 
power the eye possesses of adapting its refraction for different 
distances is called accommodation. 

This function of the eye is effected by the ciliary muscle in 
the following manner : The crystalline lens is a soft body in- 
closed in a capsule and attached by its suspensory ligament to 
the ciliary processes. The ciliary body having a fixed point at 
the corneo-scleral junction, when its muscular fibres contract, the 
attachments of the suspensory ligament are brought closer to- 
gether, the capsule becomes relaxed, and the elastic lens, which 
tends toward a spherical shape, bulges forward and becomes 
more convex. It has, in effect, added to its anterior surface 
another convex lens. As the ciliary muscle contracts more vig- 
orously, this added convex lens becomes stronger. 

If an emmetropic individual wishes to see an object situated 
25 cm. distant, he must add to his crystalline lens another lens of 
4 dioptres, i. e., one having a focal length of 25 cm. The effect 



GENERAL OPTICAL PRINCIPLES. 45 

of this extra lens is to give to rays diverging* from 25 cm. a par- 
allel direction. They will then he brought to a focus on the 
retina, by the original refractive power of the eye. 

Fig. 22. 




Increased convexity of the lens during accommodation. The solid white out- 
line of the lens, I, shows its form when relaxed. The dotted line shows the in- 
creased curvature of the anterior surface during accommodation, and its ad- 
vancement forwards into the anterior chamber, a. Z is the suspensory ligament ; 
m, the ciliary muscle ; and i, the iris. 

In the same manner, if the point is at 10 cm., an additional 
lens of 10 cm. focus is required, so that these divergent rays may 
be rendered parallel. 

For every distance of the object the degree of accommodation 
varies. It is not possible for the eye to be adapted for two dif- 
ferent distances at once. If one stands in front of a window 
pane, on which a spot is placed, and tries to see distinctly the 
spot and objects on the other side of the street, he will find that, 
when the spot is distinct, objects across the way are blurred, and 
vice versa. By means of the accommodation the eye is adjusted 
for all distances between its farthest and nearest point of distinct 
vision. 

The far point of an eye, punctum remotum, is the point from 
which come rays having the least divergence, or toward which 
go rays having the greatest convergence that allows their focus- 
ing ou the retina. From this point rays are focused on the 



46 DISEASES OF THE EYE. 

retina with the ciliary muscle entirely relaxed, the refraction of 
the eye being at its minimum, R. This point, or its distance 
from the eye, is designated r. 

The near point of an eye, pumctum proadmum, or p, is the 
point from which come the most divergent rays that can be 
focused on the retina. These are focused with the ciliary mus- 
cle contracted to its fullest extent, and the eye in its condition 
of maximum refraction, expressed by P. 

The range of accommodation, likewise denominated the power 
or amplitude of accommodation, is the difference between the re- 
fractive power of the eye accommodated for its far point and 
accommodated for its near point. This is expressed by A. 
A = P — R. 

As the refractive power is the inverse of the focal distance, the 
refractive power of the eye, when accommodated for its far point 

r, is R = -. If we express the value of r in metres, we shall then 
have the refractive power of the eye expressed in dioptres, a di- 
optre being a lens of 1 metre focus. If r = 1 metre, R = - = 

1 dioptre =1D. If r is infinitely distant, jB = -^ = 0. 

In the same manner - = P, the refractive power of the eve 
p r j 

when accommodated for its nearest point. If we obtain the value 
of p in centimetres, and wish to know how many dioptres it equals, 
we must divide 100 by the number of centimetres equal to p. 

Let p = 10 cm., then P = — — - = 10 D. If p is expressed in 

fractions of a metre, we obtain the same result : by dividing 1 by 

the value of p, in metres, 10 cm. = r-r of a m. P = -=- = 10 D., 

or, in decimals, 1-4-.1 m. = 10 D., that is, in order to focus 
rays from 10 cm., we require 10 times as much accommodation 
as is necessary to focus rays from 1 metre, and since an eye 
adapted to a distance of 1 metre exerts 1 dioptre of accom- 
modation, at a distance of T V m., or 10 centimetres, it must 
therefore exert 10 dioptres of accommodation. 



GENERAL OPTICAL PRIN< [PLES. 17 

To find the rang* of accommodation, we must first determine 
the far point. This is accomplished by means of test letters held 

in front of the patient. If the patient has maximum acuity of 

distant vision, r is infinite, [wheni2 = ^ = 0] or negative. If 
vision is less than normal at 6 metres, hut i- normal at 1.5 

metres, /• = 1.5 metres; R then = . > = .66 D. If distant vis- 
ion becomes or remains distinct when a convex glass of 2 D. is 
placed before the eye, then R — — 2D.; that is, the far point of 
such an eye is negative, a point behind the retina toward which 
ray- converge. This condition is further discussed, page 143. 

The near point is found by holding in front of the patient 
finely-printed reading matter, and measuring the nearest distance 
to his eye at which this is distinct. For this purpose large print 
may be reduced by photo-lithographing, so as to subtend the 
standard angle of 5' at a distance of 25 cm. or less, and is 
usually arranged on suitably shaped cards/ 

The formula for obtaining the range of accommodation is A = 

P — R. If p is at 20 cm., P = -^— = 5 D., and r is at infinity, 

R = 0, then J = P=5D. This is the case in emmetropia. 

If p is at 10 cm., P = ~ = 10 D., and r is at 25 cm., R = — 
1U '!■) 

= 4 D., then 4=loD-4D=i] D. This is the case in my- 
opia of 4 D. P is greater than A. 

If p is at 50 cm., P = — - = 2 D., and /• is negative, — 25 

cm. R == -2=— 4D. 4 = 2— (— 4)=2 + 4 = 6D. This 

is the range of accommodation in a hypermetrope of 4 D., and 
equals the sum of P and P. 1 

The near point is closer to the eye in young life while the lens 
is soft ; as age advances the lens becomes harder and the near 
point gradually recedes until, at about the age of 70, the near 

1 p refers to the distance of the near point in centimetres. Prefers to the 
refractive power of the eye in accommodation for p. r refers to the distance 
of the far point. R refers to the refraction of the eye when accommodated 
for r. 



48 



DISEASES OF THE EYE. 



point has reached infinity, and p and r then coincide, and there 
is no range of accommodation. 

The failure of the accommodation due to age is termed pres- 
byopia. This is more fully described under Presbyopia (see 
page 174). 

The range of accommodation is nearly constant for the same 
age, so that if p is nearer than it should be myopia may be 

Fig. 23. 



& /f re ss 


3!) SS to 


*s jo .rs en es 


» 


rs #■ 


u 


























































13 






























11 


































\f> 


























10 






























S 






























f 

c 






















































































j 


























































j 






























z 






























I 






























n 


































r 
















"? 




P 




? 






























.3 
.4 























































































Diagram of the range of accommodation (Landolt). The vertical column of 
figures on the left hand side indicates the dioptres of accommodation. The hori- 
zontal line of fiffures at the top represents the ages. The curved line, p p, repre- 
sents the refractive power of the eye at different ages, when accommodated for 
its near point. The line >• r represents the refraction of the eye when relaxed for 
its far point. At 55 years it is supposed to become hypermetropic ; r then be- 
comes negative. 

suspected, or if it is farther away than the average, hyperme- 
tropia. (Fig. 23.) For this purpose the table given on page 
49 is used, which records the average of P in dioptres and p in 
centimetres for the different ages. 



GENERAL OPTICAL PRINCIPLES. 



49 



14 dioptres 


V 


= 


7 cm 


12 


i t 


a 


= 


8.3" 


10 


K 


u 


= 


10 " 


8.5 


(i 


it 


= 


12 " 


7 


" 


" 


= 


14 " 


5.5 


(f 


" 


= 


18 " 


4.5 


C< 


i i 


= 


22 " 


3.5 


f < 


a 


= 


28 " 


2.5 


" 


t 4 


= 


40 " 


1.75 


K 


" 


= 


55' " 


1 


i< 


" 


= 


100 " 


.75 


u 


K 


= 


133 " 


.25 


" 


it 


= 


400 " 





a 


" 


= 


oc 



Table of the range of accommodation. 

10 years 

15 " 

20 " 

25 " 

30 " 

35 " 

40 " 

45 " 

50 " 

55 " 

60 " 

65 " 

70 " 

75 " 

The ciliary muscle is most fully developed in hypermetropic 
eyes ; the circular fibres are here very numerous. In myopic 
eyes they are less numerous and sometimes wanting. As a result 
of this, the accommodation is greater in hyperrnetropia, and more 
feeble in myopia. 

This point is of importance in connection with the prescribing 
of glasses. It sometimes is impossible to make the hypermetrope 
relax his accommodation entirely, even for distance, and the 
myope is often distressed if he is forced to accommodate by con- 
cave glasses. In young persons the accommodation renders 
hypermetropia latent, and the eye may appear emmetropic or 
even myopic ; it also causes emmetropia to simulate myopia, and 
myopia to appear higher than it actually is. 

Angle Gamma: Angle Alpha. — The eye in looking at any 
object is directed forwards in such a manner that the image is 
formed on the macula lutea. The eye is now said to " fix" the 
object. A line, drawn from the object thus fixed, to the macula 
lutea, is called the visual line, or visual axis. 

The point about which the eye revolves, in order to be brought 
into this position, is called the centre of rotation, and has its posi- 
tion 14 mm. back of the cornea. The line which connects the object 
with the centre of rotation is designated the line of f. ration. 

The optic axis is an imaginary line, passing through the centre 
of the cornea and lens and the point of rotation, to the posterior pole 
of the eye, i. e., a point usually between the macula and optic papilla. 



50 



DISEASES OF THE EYE. 



If the macula lutea coincided with the posterior extremity of 
the optic axis, the visual line, line of fixation, and optic axis 



Fig 24. 




Angle alpha and angle gamma. (Landolt.) A A', optic axis; F, visual 
line ; M, line of fixation ; E L, major axis of corneal ellipse. The line of fixa- 
tion does not correspond with the optic axis, but forms the angle MA, angle 
gamma nearly equal to the angle X A, formed by the visual line with the 
optic axis. X A may be considered as the angle gamma. The visual line does 
not pass through the summit of the corneal curve, E, but forms with the axis of 
the cornea, EL, the angle X E, the angle alpha. 

would also coincide. Generally, this coincidence does not exist. 
In emmetropia and hypermetropia the optic axis passes to the 









GENERAL OPTICAL PRINCIPLES. 51 

inner side of the macula Lutea, and the visual line and line of 
fixation then form angles with the optic axis. In Fig. 23 .1 .1' 
is the optic axis passing through the centre of the cornea, Cthe 
nodal points of the eye, K' A'", and the centre of rotation, M. 
F\a the visual line connecting the object, 0, with the fovea, F. 
O M is the line of fixation, drawn from to the centre of rota- 
tion, M. The eye, in order to fix 0, has its optic axis, .4 A,' 
deviated outwards. The angle formed by the line of fixation, 
M } with the optic axis ^1 A', is called the angle gamma, y, or, 
the angle formed by the visual line with the optic axis may be 
considered as the angle gamma. 

The significance of this angle is, that a person while really 
fixing an object seems to have a divergence of the visual lines 
— divergent squint. In estimating the degree of a divergent 
strabismus it is necessary to consider the value of this angle. 
The amount of the angle gamma is usually 5°, but it may reach 
as much as 10°. When the anterior extremity of the visual line 
passes to the inner side of the optic axis, the angle gamma is 
positive, or + ; this is the usual condition in emmetropia and 
hypermetropia. The convergence of the visual line exceeds the 
convergence of the optic axis by the amount of this angle. 
When the visual line coincides with the optic axis there is no 
angle gamma. The visual line in high myopia sometimes passes 
to the outer side of the optic axis. The eyeball must then be 
deviated inwards in order to fix on the object. This produces 
the effect of a convergent squint. It must be distinguished from 
squint ; and if convergent strabismus also exists, the value of this 
angle must be deducted from the apparent squint. In this latter 
form of the angle gamma, where the anterior extremity of the 
visual line passes to the outside of the optic axis, the angle gamma 
is negative, or — . The convergence of the visual line is less than 
the convergence of the optic axis by the amount of this angle. 

The amount of this angle may be measured by placing the 
patient before the perimeter as if his field were to be taken. The 
eye is fixed on the central point, and a lighted candle is moved 
along the are in a horizontal direction until its reflection is ob- 
tained from the portion of the cornea corresponding to the centre 



52 DISEASES OF THE EYE. 

of the pupil. The position of the candle may now be read from 
the arc in degrees, and represents the size of the angle gamma. 

The apex of the cornea does not generally coincide with the 
centre of the cornea, but is displaced laterally. The major axis 
of the corneal ellipse, represented in the figure by EL, therefore 
forms an angle with the visual line. The angle alpha is the angle 
formed by the visual line with the major axis of the corneal 
ellipse. It is positive when the major axis of the cornea passes 
to the outer side of the visual line ; if the corneal axis passes to 
the inner side of the visual line, the angle alpha is negative. In 
the figure the angle O X A is the angle gamma; the angle X E 
is the angle alpha . 

From what has been said it will be seen that the visual line is 
a secondary axis to the optical system of the eye. The oblique 
position of the refracting surfaces to the visual line may be the 
cause of an increased refraction in the horizontal meridian con- 
stituting astigmatism. 

CONVERGENCE. 

In the visual act of one eye the sensation conveyed to the brain 
is projected outwards over the same course by which it arrived, 
that is, the object is referred to a position in the field of vision 
which it actually occupies. If the projection outwards of the 
images of the two eyes is such that they overlie each other, the 
person will have single vision ; if, however, they are projected 
in different positions, double vision is the result. 

The images are projected in different positions when they 
are not formed on identical points of the two retinas. The 
fovea centralis being the most sensitive portion of the retina, the 
eye is naturally so directed towards an object that the image is 
formed upon it. The eye is then said to fix the object. The 
fovea? of the two eyes are identical points, and images formed on 
them are projected outwards so as to overlie, or fuse into each 
other ; points at a corresponding distance to the right of each 
fovea, or to the left, or upwards or downwards, are also identi- 
cal, and images formed on them produce but a single impression. 
Objects in the field of vision to the right of the point of fixation 
form a retinal image to the left of the fovea. Objects to the left 



GENERAL OPTICAL PRINCIPLES. 



53 



Fig. 25. 



of the point of fixation form an image to the right of the fovea. 
(See Figs. L5 and 21.) All images formed on the retina to the 
right of the fovea are projected outwards to the left. Those 
formed on the left of the fovea are projected t<> the right; in the 
same way those formed on the upper part of the retina are pro- 
jected downwards, those formed on the 
lower part of the retina are projected 
upwards. 

The eyeballs are separated laterally, 
on the average, U4 mm. in adult eyes. 
In looking- at a distant object, if the axes 
of the eyes are parallel, the images are 
formed on corresponding points of the 
retinas, but when the object is at some 
nearer point the eyes must be turned 
inwards in fixing the object, to compen- 
sate for their lateral separation. This 
function of the eyes is termed conver- 
gence. 

The eyeball is rotated inwards by the 
internal rectus muscle, so that its visual 
line is directed towards the object. This 
function is very closely associated with 
that of accommodation ; one cannot act 
in any very great degree without the 
other also coming into play. The move- 
ment inwards of the eye is measured 
by the angular deviation of the visual 
line, termed the angle of convergence. 

The unit of convergence is the angle 
through which the visual axis moves 
to fix on a point 1 metre distant. 
This is termed one-metre angle of con- 
vergence (Xagel). (Fig. 25.) If the 
object fixed is only h metre distant, 
the movement will be twice as great ; 

it is then 2-metre angles. A point i of , r . , , 

p i rf Metre angles of convergence 

a metre would require 3-metre angles, (Landoit.) 



54 DISEASES OF THE EYE. 

and so on. 10-metre angles of convergence mean that the eve is 
directed to a point only T ^ of a metre distant. 

Metre Angle. — In the figure, Oand 0' represent the centres of rotation 
of the two eyes ; O O' is the distance between these points, termed the 
interocular distance. It is measured by the distance between the pupils 
during fixation for remote objects. O M is one-half this distance. 

The line CM is perpendicular to O O'. When the object is situated 
on the line CM the convergence of each eye is equal. When the visual 
lines J and J 0' are parallel, the angle of convergence is nil; when, 
however, the visual lines are directed to C", one metre distant, O J has 
deviated to C. JO C is the angle through which the visual line has 
moved to fix on C". This is one-metre angle of convergence. 

( ' .1/ being parallel to J O, C M is equal to J O C. 

In the right-angled triangle C il/, O M equals £ the interocular 
distance. 

C = the distance of the point of fixation. 

■ ' „ — the sine of the angle O C M. 
(J C 

The average interocular distance is 04 mm. M= h of 64, or 32 mm. 

O C is 1 metre distant. 

O V 32 

= = .032 = the sine of 1-metre alible. This corresponds to, 

OC 1000 ° * 

1° .50'. 

If the eye is directed to a point £ metre distant, C", the visual line 
will deviate twice as much ; that is, it deviates 32 mm. at -1 metre dis- 
tance. If the point of fixation is only ,\of a metre distant, the amount 
of convergence will equal 10-metre angles. 

To find the value of this in degrees we employ the same formula as 
above— 

9J^ = sine of angle OC 10 M. <>M= 32. C'° = T \ metre = 100 

3° 
mm. , ~ = .32, the sine of angle of convergence, = IS 40'. 
100 ° 

The value of the metre angles in degrees is obtained very nearly by 
multiplying 1 50' by the number of metre angles. The value of the 
metre angle varies with the interocular distance, and as there is con- 
siderable difference in this distance a separate calculation is necessary 

for each individual. 

A more simple method of determining the value of %e metre 

angle is to find its relation to the centrad. The centrad is a 
prism which deviates a ray the y, 1 ,^ part of the radius, measured 
on the arc (see page L'4j. The deviation of the metre angle is 



i. IN ERAL OPTICAL I'KIN< IP 

measured on the sine. For the angles obtained the sine and arc 
are almost equal. 

One-metre angle equals a deviation of 32 mm. (the average 
distance between the centres of rotation of the eyes being 64 nun.) 
at 1 metre distances '■)- in 1000 nun., or 3.2 in 100 = 3.2 cen- 
trads. One centred = .57295 , 3.2 centrads= 1 50'. Ten- 
metre angles equal a deviation of 32 nun. in /,, metre, 100 nun., 32 
in 100, or 32 centrads= 18 C 20'. A 32-centrad prism not only 
gives us the value of 10-metre angles of convergence, but placed 
before the eye, with the base inwards, it takes the place of 10-metre 
angles of convergence, so that the eye, without any convergence, 
would sec an object on the line C M, 10 centimetres distant, as if 
it were situated at a remote distance. 

The convergence becomes greater as the point of fixation ap- 
proaches nearer. The number of metre angles is, therefore, in- 
versely proportional to the distance expressed in metre-. We 
thus designate the convergence in terms which indicate the same 
number of units of convergence as the dioptres of accommodation 
necessary for the same distance. An emmetrope, in looking at 
an object J metre distant, would employ 4-metre angles of con- 
. ace, and I dioptres of accommodation. 

The amplitude of convergence is the number of metre angles 
of convergence which the eyes can call into action. It is meas- 
ured from the far jpgjbii of convergence to the near point of con- 
r< i-i/i nee. 

The far point of convergence is the point to which the visual 
lines are directed when the convergence is relaxed to its utmo-t ; 
the near point of convergence i- the point to which the visual lines 
are directed when the convergence is at its maximum. If in the 
minimum degree of convergence the visual lines are parallel, 
the far point of convergence will be at an infinite distance. 
1 Fsually the visual lines actually diverge forward at the minimum 
of convergence, constituting an outward squint, and converge by 
their posterior extremities toward a point behind the eve-. A\ hen 
this is the case, the far point and a portion of the amplitude of 
convergence are negative. In some cases, with the convergence 
relaxed to its fullest extent the visual lines still deviate inward, 



56 DISEASES OF THE EYE. 

constituting an internal squint. The convergence will in such a 
case always be entirely positive. 

The two functions of convergence and accommodation, while 
closely associated, still have some latitude of movement; it is 
possible to accommodate several dioptres without any conver- 
gence, and to converge several metre angles without accommo- 
dation. At the far point of accommodation and convergence the 
accommodation has somewhat more play ; at the near point, how- 
ever, the convergence has much the larger movement. The am- 
plitude of convergence does not always diminish with age as does 
the accommodation. But many persons show some tendency to 
diminished convergence-power, or endurance, from changes in the 
ocular muscles, similar in kind, though less in degree, to the 
senile changes that usually occur in other parts of the muscular 
system. 



EXTERNAL EXAMINATION OF THE EYE. 57 



CHAPTER II. 

EXAMINATION OF THE PATIENT AND EXTERNAL EXAMINATION 

OF THE EYE. 

A systematic method of examination of each case should be 
practised in order to secure the preservation of careful records. 
For this purpose the following order of examination may be 
used •} — 

Name and residence. 

Age, sex, race, married or single. 

Family history : hereditary tendencies ; general and ocular health 
of parents, brothers, sisters, etc. 

Personal history : children, their number and health ; miscarriages ; 
former illnesses ; syphilis and gonorrhoea ; injuries. 

Occupation : relation of work to present indisposition. 

Habits : brain use ; tobacco ; alcohol ; narcotics ; sexual. 

Date and mode of onset and supposed cause of present trouble ; out- 
line of its course. 

Organs of digestion : teeth ; tongue ; stomach ; bowels. 

Organs of respiration : nose ; throat ; lungs. 

Organs of circulation : heart ; pulse ; blood. 

Kidneys : examination of urine. 

Abdominal organs : liver ; spleen. 

Organs of generation : menses ; leucorrhoea ; uterine disease. 

Nervous system : intelligence; evidences of hysteria ; hallucinations; 
sleep ; vertigo ; gait ; station ; tendon and muscle jerks ; paralysis ; 
tremor ; pain ; subjective sensations ; convulsions ; headaches and their 
position. 

Eyes : inspection of the skull and orbits (symmetry or asymmetry) ; 
ciliary borders; puncta lachrymalia ; upper and lower cul-de-sacs; 
conjunctivae; caruncles; cornese (oblique illumination and loupe); 
irides (mobility and color) ; anterior chambers (depth and character of 
contents) ; vision ; accommodation ; balance external eye muscles ; ad- 
duction, abduction, sursumduction ; position of eyes ; mobility of globe ; 
tension; light-sense; color-sense; fields of vision ; ophthalmoscope. 

1 This order of examination is modified from the one employed by Dr. Weir 
Mitchell in the Infirmary for Nervous Diseases. 



58 



DISEASES OF THE EYE. 



This schedule of examination must be modified to suit indi- 
vidual cases, as these present trivial local lesions directly discover- 
able by inspection, or forms of disease requiring detailed study 
for their proper interpretation. 

Direct Inspection of the Eye. — After the preliminary exami- 
nation which the case demands, the surgeon proceeds to the direct 
inspection of the eye. The surfaces of the lids should be ex- 
amined for swollen superficial veins, a common index of inflam- 
mation of the globe ; their edges for inflammation, parasites, and 
misplaced cilia ; the puncta for permeability, pressure at the same 
time being made over the lachrymal sac in order to express from 
it through the puncta any contained fluid ; the upper and lower 
conjunctival cul-de-sac for accumulated secretion, granulations, 
and foreign bodies; the palpebral conjunctiva for hardened secre- 
tion in glands; the caruncles for swelling, attached foreign bodies, 
and irritation by incurved cilia ; and the conjunctiva for the in- 
formation to be derived from its bloodvessels. 

Fig. 26. 




Position of bands iu the act of everting the eyelid. 

In order to evert the lid, observe the following rules : Require 
the patient to turn the eye strongly downward, seize gently the 



EXTERNAL EXAMINATION OF THE EYE. 



59 



central eyelashes of the upper lid between the index finger and 
thumb of the left hand, draw the lid downward and away from 
the ball, place the point of the thumb of the right hand abov< 
the tarsal cartilage of the Lid which is to be everted, the remain- 
ing fingers being steadied on the brow, and by a quick move- 

Fig. 27. 




Eyelid everted for examination of its under surface and the upper part of globe. 



ment turn the edge of the lid over the point of the thumb, 
while this is simultaneously depressed. During the entire 
manoeuvre insist upon the downward direction of the patient's 
eyes; otherwise, the lid cannot be turned without undue force 
and pain. 

Bloodvessels of the Conjunctiva. — In health only a few con- 
Bpicuous bloodvessels are to be observed ; in inflammation many 
more become visible. The arteries of the conjunctiva are derived 
from the palpebral and lachrymal branches of the ophthalmic; 
those of the episcleral tissue arise from the anterior ciliary branches 
of the ophthalmic, while the border of the cornea is surrounded by 
a plexus of capillar} 7 loops derived from the anterior ciliary ves- 



60 



DISEASES OF THE EYE. 



sels. This blood supply may be conveniently divided, as Mr, 
Nettleship has done, into three systems : — 

System I. Posterior conjunctival vessels, whose congestion pro- 
duces a bright red, velvety color, moving, on pressure of the eye- 
lids, with the shifting of the conjunctiva, usually associated 
with muco-purulent secretion, and indicating conjunctivitis. 

Fig. 28. 



tdnp 




Vessels of the front of the eyeball, cm, ciliary muscle. Ch, choroid. Scl, 
sclerotic. V V, vena vorticosa. Z, marginal loop-plexus of cornea. Ant. and 
Post. Conj., anterior and posterior conjunctival vessels. Ant. Cil. A. and V, 
anterior ciliary arteries and veins. (After Nettleship's alteration from Leber.) 

System II. Anterior ciliary vessels, composed of perforating 
and non-perforating arteries and veins. The perforating arteries, 
which supply the sclerotic, iris, and ciliary bodies, are the branches 
seen in health entering about 5 mm. from the corneal margin, their 



EXTERNAL EXAMINATION OF THE EYE. 61 

points of entrance, in dark-complexioned people, often being dis- 
tinctly tinted. 

The non-perforating (episcleral) branches, invisible in the nor- 
mal eye, produce, when congested, a pink zone surrounding the 
cornea (" ciliary congestion," "circum-corneal /one"), not moving 
on pressure of the lids with the shifting of the conjunctiva, 
unassociated with purulent discharge, and one indication of 
iritis. 

The perforating veins and their non-perforating (episcleral) 
twigs, when congested, create a zone of dusky hue, often a 
symptom of glaucoma, or appear in unequal deep-seated patches 
of lilac or violaceous color, pointing to cyclitis or scleritis. 

System III. Anterior conjunctival vessels and the plexus of capil- 
laries surrounding the cornea, derived from anterior ciliary vessels 
through whose numerous small branches anastomosis between 
Sy-tem I. and II. takes place. Their congestion produces a circle 
of bright-red injection, often partly on the cornea, a sign of in- 
flammation of this membrane, and typified in the early vascular 
stages of interstitial keratitis. (See page 285.) 

In addition to these three varieties of congestion numerous 
departures are noticeable, making it impossible to separate the 
form and specify the individual system involved. In these types 
is found a definite local injection, as the leash of vessels passing 
to a corneal ulcer ; or all the systems are commingled in a general 
inflammation. 

Inspection of the Cornea reveals inflammation, ulceration, opac- 
ities, and foreign bodies. Slight irregularities are detected by 
placing the patient before a window, while the eyes are made to 
follow the uplifted finger held about one foot from the face, and 
moved in various directions. The image of the window-bars 
reflected from the cornea will be broken as it crosses the spot of 
inequality. 

A more accurate method is to employ a keratoscope. This in- 
strument consists of a disc shaped like a target, upon which are 
drawn concentric black circles, a sight hole being in the centre. 
The patient is placed with his back to the window while the 
surgeon holds the instrument in front of the eye, and, looking 
through the central aperture, observes the reflections of the circles 



62 



DISEASES OF THE EYE. 



from the cornea. If these are broken or distorted, the indica- 
tions of irregularity in the surface are present. 

Minute abrasions and ulcers, if suspected, and yet not deter- 
mined, may be found by dropping into the eye a concentrated 
alkaline solution of jiuor esc in (Gruebler's fluorescin, 2 per cent. ; 
carbonate of soda, 3.5 per cent.), which colors green that portion 
of the cornea deprived of its epithelium, "while the healthy epi- 
thelium remains unaffected. For example, the coloration takes 
place around a foreign body in the cornea, the foreign body itself 
appearing as a black dot in the centre of the green area. The 
observation with fluorescin was made originally by Straub. 

Oblique Illumination is a method of examination by which 
the cornea, the anterior chamber, the iris, and, if the pupil is 
dilated, the lens and even the anterior layers of the vitreous may 
be studied. The surgeon places the patient two feet from the 
source of illumination, and focuses a beam of light with a two-inch 
or three-inch lens upon the cornea, at the same time observing the 
surface under examination through a lens of the same focal dis- 
tance, held between the thumb and forefinger, the disengaged 
fingers being utilized to elevate the upper lid. (Fig. 29.) 

Fig. 29. 




Method of oblique illumination. 

The distance of the lens must be varied slightly, according 
as the cornea, iris, or crystalline lens is brought within its focus, 



EXTERNAL EXAMINATION OF THE EYE. 63 

the patient being required to look up. down and to either .side, 
while all the anterior surfaces and media of the eye are illumi- 
oated. In order to detect foreign bodies in the cornea, the light 
should lie directed at an acute angle. If the posterior poleofthi 
lens is to be examined, the light is thrown perpendicularly into 
the pupil, the surgeon placing hi.- eye in the same direction, with- 
out interfering with the light. 

By this method minute abrasions, previously undetected foreign 
bodies, channels of old vessels, and other corneal changes may be 
examined. The character of the aqueous humor, the depth of 
the anterior chamber, the surface of the iris, the presence of 
synechia?, small tumors, atrophic fibres, and persisting pupillary 
membrane are evident, and, finally, opacities in the anterior cap- 
sule and axis of the lens are discoverable. 

The routine examination by means of lateral illumination, pro- 
vided the eye is unaffected with an inflammation associated with 
so much photophobia that this is not possible, will often afford 
information unattainable by other methods. 

The Corneal Loupe. — This is a lens, properly mounted, by 
which the cornea is strongly magnified, and which should be em- 
ployed with oblique illumination. A " corneal micro-cope." or 
a specially prepared lens of high power, permits the study of 
minute changes in this membrane, and is utilized for the exami- 
nation of the traces of former vascularization, particularly after 
interstitial keratitis (see page 286), and by its help even the cir- 
culation of the blood in the vessels of a pannus may lie studied. 

The Color of the Iris. — The color of the irides varies ; blue 
and gray are the predominating hues ; brown occurs next in 
frequency ; while the various admixtures produce yellow and 
green shades. Black irides are never seen, and the color of the 
iris of all new-born children is of a light grayish-blue; the 
stromal pigment is developed subsequently. 1 

Slight differences in shade between the two irides are not 
uncommon ; more rarely, even in health, the irides differ in 
color (chromatic asymmetry), one being brown or greenish, the 

1 Ely records two dark irides in more than 1000 newly-born children ; in 
one the child was a negro. 



64 DISEASES OF THE EYE. 

other blue or gray. Almost invariably, in cases of this sort, one 
iris corresponds in color with the irides of one parent, and the 
remaining iris with those of the other parent. Instead of uni- 
form pigmentation, a single triangular patch, or several irregular 
spots of dark color, may appear upon one or both irides (piebald 
irides). This is sometimes temporary. Chromatic asymmetry, 
while perfectly compatible with health, has been observed in pa- 
tients with neuropathic tendencies — chorea and epilepsy — (Fere*); 
in other instances, there is liability to disease on the part of the 
lighter eye (cataract). This phenomenon may be present in sev- 
eral members of the same family. 

Discoloration from disease results in one iris being green, that 
of the fellow being blue, and indicates iritis or cyclitis ; it is 
often an early symptom of inflammation of the iris, and should 
be looked for in every inflamed eye. When the dark segments 
seen in a piebald iris are small, they have been mistaken by 
incautious observers for foreign bodies. 

The Pupil. — The size of the pupil in health varies with 
exposure to light, and with accommodation and convergence. 
There is no physiological standard by which to base a measure- 
ment. The pupil is generally smaller in old age, in blue irides, 
and in eyes with hypermetropic refraction ; it is larger in 
youth, in dark irides, and in eyes with myopic refraction. 
With the accommodation at rest, the diameter of the pupil 
varies from 2.44 to 5.82 mm., the average diameter being 4.14 
mm. (Woinow). The position of the pupil is a little to the nasal 
side of the cornea, and, under similar illumination, the pupils 
should be round and of equal size. 1 

It is much to be regretted that the recorded variations in the 
diameter of the pupil are commonly imperfect, and the loose state- 
ments, " pupils dilated," " pupils contracted," " pupils medium- 
sized," have crept into many reports. 

Measurement of »the Pupil. — The pupil can be measured 
approximately by holding before it a rule, marked in millimetres, 
and noting the number of spaces its width occupies. The chief 

1 In contrast to this statement, the observation of Iwanow deserves mention. 
This observer found, among 134 healthy young military recruits, equal width 
of pupil in only 12. The right pupil was larger in 49, and the left in 73. 




EXTERNAL EXAMINATION OF THE EYE. 65 

objection to this method is, that the distance subtended on the 
rule Is less than the diameter of the pupil, in proportion as the 
distance from the observer's eye is less to the rule than to the 
pupil (Jackson). 

A great variety of instruments, known as pupillometers, have 
been devised for the accurate measurement of the width of the 
pupil. A very simple and serviceable 
device is Randall's modification of lg " * 

Follin's instrument, which consists of 
a scale of circles held close to the ob- 
served eye, the scale being slowly ro- 
tated until that circle which matches 
the pupil in size is reached. 

Priestley Smith's keratometer is a 
scale situated between two plano-con- 
vex lenses. The surgeon places his 
eye at the principal focus of the com- Simple P u P m °™^. 

bination, and, holding the scale before the patient's eye, observes 
that the cornea, or pupil, subtends on the scale exactly its width. 

All examinations should be made under a uniformly strong 
light, and the character of light should be stated. 

Mobility of the Iris. — The reflex mobility of the iris is tested 
to find the presence of attachments between the iris and the lens 
(synechia), or immobility from atrophy of the iris, or to examine 
the sensitiveness to light of the retina or visual centre. 

The patient is placed before a window in diffuse daylight, and 
one eye is carefully excluded. He is directed to look into the 
distance with the exposed eye, which is then shaded, and, if it is 
normal, a considerable dilatation of the pupil will occur. On 
removal of the covering hand or card, contraction to the same 
size as that which existed before the test was applied takes place 
(direct reflex action of the pupil). During this examination, the 
other pupil will act in unison with its fellow (consensual, or in- 
direct reflex action), and in normal eyes the pupils should be 
equal, not only with both eyes open, but with one eye shaded. 

When the covering hand is removed from the eye directed 
toward the light, the dilatation which existed in the pupil yields 
5 






66 DISEASES OF THE EYE. 

to a contraction, succeeded in a moment by a slight dilatation and 
again a contraction, oscillating thus for a moment until it settles 
to the original size. This is called " hippus" a phenomenon 
seen in an exaggerated degree in hysteria, mania, and other 
nervous disorders. The explanation of hippus is that each con- 
traction of the pupil, by diminishing the supply of light to the 
retina, contains in itself the cause of the succeeding dilatation ; 
and, conversely, each dilatation sets in motion the succeeding con- 
traction, until at last equilibrium is attained (Swanzy). 

During the whole process of testing the reflex mobility of the 
iris the observed eye must be steadily fixed upon a distant point ; 
otherwise the influence of accommodation or convergence will 
arise. 

The contraction of the pupil, which occurs when the eye is 
exposed to a source of light in the manner described, is a reflex 
phenomenon, the optic nerve being the afferent pathway, and the 
oculo-motor the efferent nerve going to the sphincter of the iris, 
the communicating fibres between the corpora quadrigemina and 
the centre for the third nerve enabling the reflex to take place. 

The pupils also contract when the eyes are directed to a near 
object, or, in other words, contraction takes place under the in- 
fluence of accommodation and convergence (associated action of 
tke pupils). The extent of this action is less than in the reflex 
motions, and is more closely connected with convergence than 
with accommodation. Accommodation increases pupillary con- 
traction, but this contraction does not take place under the 
influence of accommodation unassociated with convergence ; it 
does occur with convergence without the act of accommodation. 

Dilatation of the pupil occurs in glaucoma, in cases of non- 
conductivity of light (atrophy), in orbital disease, and under the 
influence of mydriatics. It is further seen in fright, emotion, 
amemia, in depressed nervous tone, aortic insufficiency, cutaneous 
stimulation (skin reflex), and irritation of the cervical sympathetic. 

In diseases of the nervous system, dilatation of the pupil when 
of cerebral origin indicates extensive lesion ; when of spinal 
origin, irritation of the part (McEwen). Systematic writers have 
divided dilatation into irritation mydriasis, caused by irritation of 






EXTERNAL EXAMINATION OF THE EYE. 67 

the ]>u])il dilating centre or fibres, and paralytic mydriasis (iridople- 
gia), caused by paralysis of the pupil contracting centre or fibres. 

Contraction of the pupil (m/yosis) appears in congestions of the 
iris, in certain levers, in plethora, venous obstruction, mitral dis- 
ease, pulmonary congestion, paralysis of the sympathetic, and 
under the influence of myotics. 

If the myosis is of cerebral origin, it indicates an early irrita- 
tive stage of the affection (meningitis, etc.) ; if of spinal origin, 
a depression, paralysis, or even destruction of the part (McEwen). 

Small pupils are connected with degeneration of the posterior 
columns of the cord {spina/ myosis). Pupils unaffected by the 
changes of light and shade, but contracting under the influence 
of convergence of the visual axes, known as Argyll-Robertson 
pupils, are frequent in tabes. 

Systematic writers divide contraction of the pupil into irrita- 
tion and paralytic myosis. The same factors which cause myosis 
may cause mydriasis, the determining factor being the degree and 
the duration of the lesion. 

Unequal pupils are rarely seen in health. 1 If there is recent 
wide dilatation of one pupil and no disease of the eye, the instilla- 
tion of a mydriatic may be suspected. Unequal pupils occur 
in eyes with widely dissimilar refraction, if one eye is blind, 
in aneurism, dental disease, traumatism, and in diseases of the 
nervous system. If the disease is cerebral, the inequality de- 
notes unilateral or focal brain disease. It is not uncommon in 
tabes, disseminated sclerosis, and paretic dementia. Varying in- 
equality of the pupils, or a one-sided mydriasis now occurring on 
the one side and now on the other, is a serious premonitory 
symptom of insanity. 

Testing Acuteness of Vision. — The acuity of vision is the 
power of distinguishing form and size, and is a function of the 
macula lutea, the peripheral portions of the retina having only 
indifferent ability to distinguish form and size. 

In order to determine the acuity of sight test-types are em- 
ployed, in which the letters are of various sizes, and constructed 
according to the methods described on page 43. 

1 See foot-note, page 64. 



G8 DISEASES OF THE EYE. 

When it is desired to test the acuity of vision the patient is 
placed six metres from the type-card, in a well-lighted room, and 
each eye is tried separately. If the letters of No. 6 (twenty feet 
approximately) are read, vision is normal, or 1, but if, at the 
same distance, no smaller letters than those numbered 18 (sixty 
feet) can be discerned, vision is J. It is usual to express these 

results according; to the formula V = — , in which V stands for 

visual acuteness, d for the distance of the patient from the card, 
and D for the distance at which the type should be read ; so 

that in these instances the vision would be recorded -x and r^j or 

20 20 

in feet, — and — . The rays coming from the letters at six 

metres distance have so little divergence when they reach the 
eye that they may be considered parallel. Hence, if the patient 
sees distinctly at this distance, his vision is perfect at the longest 
range. 1 Any other distance may be chosen, provided it does not 
place the patient closer to the test-card than three metres, at which 
close range the function of accommodation would introduce an 
element of inaccuracy. Thus, the scale made use of by De Wecker, 

5/15 \ 

and elaborated by Oliver, assumes p ( — approximately) in- 
stead of 7T, as -• 
o 1 

The acuity of sight, as tested with types constructed on the 
basis of an angle of five minutes, does not always yield accurately 
the highest vision attainable ; indeed, many good eyes possess a 
vision of f of the standard angle. For this reason Dr. James 
Wallace has arranged a series of test-types in which an angle of 
four minutes has been substituted as the basis of each letter. 
(Fig. 31.) 

For the purpose of a control test, and also for determining 
visual acuity in illiterate persons, cards are employed on which 
a number of differently arranged dots are placed, of sizes which 
should be counted at different distances, and among these Bur- 
chardt's international tests are the most useful. 

1 Compare page 47. 



EXTERNAL I.X A M IN ATI< >.\ OF THE EYE 69 



H 



If the patient fails to de- Fig. 31. 

cipher the largest letter- at 

1 ° mriERS 

thr distance employed, he " 

should be moved closer to 

the card ; thus, lie may be 

unable to read the type 

numbered 60, at six me- ^^^ ^^^ w 

tres, Inn may discern this J Lj 

at 4 metres, V= — or — 
60 15 

of normal. Still further de- » J |k ■ II A 7 * 

preeiation <>t' visual acuity is |^J |™ | Jp\ 

recorded by requiring the 

subject to count the out- 49 

stretched ringers at various t- i L* 

distances, 2, 3, or 6 feet, 

V= counting fingers at 2 « D O 7 E" J " 

feet. When the ability to 

distinguish form (qualitative 

light perception) no longer H N G C O D 

exists, the perception of light 

should be tried by alternately u v Y S B R A 24S 

screening and shading the 

eye, or by illuminating the 6 xkzenhfp '" 

eye with light reflected from 

a mirror. 

& P F B R A H N Z «* 

Light-sense. — Having de- 
termined the acuity of vision 

4 KXYVCODO Hi 

by means of the test-letters, 
the examiner has ascertained 
the form-sense, and may pro- 
ceed to try a Second Sllbdivi- Diagram of test-letters reduced one-quarter. 

sion of the sense of sight, the 

light-sense, which is the power possessed by the retina, or centre 
of vision, of appreciating variations in the intensity of the source 
of illumination. 

An instrument, called a photometer, is employed for this purpose, 
and consists essentially of an apparatus by which the intensity 



70 DISEASES OF THE EYE. 

of two sources of light may be compared. The patient, looking 
into the instrument, sees two equally bright discs. One disc is 
now made darker, and the power of the eye to perceive the dif- 
ference in the illumination of the two discs ascertained ; or one 
disc is made entirely dark, and then gradually illuminated, and 
the smallest degree of light noted by which the patient can 
perceive the disc coming from the darkness. The former is 
called the light-difference (L. D.), and the latter the light-mini- 
mum (L. M.). Some information in regard to the light-sense 
may be obtained by testing the acuity of vision on two cards, 
under a different degree of illumination, and by comparing the 
results with a similar examination of a subject believed to have 
normal power of appreciating different degrees of illumination. 
Indeed, a very important examination in slight retinal changes 
and minor disturbances about the macula consists in ascertaining 
the acuity of sight under full and under diminished illumination. 

Color-sense. — A third subdivision of the sense of sight is the 
color-sense, or the power which the retina has of perceiving color, 
or that sensation which results from the impression of light waves 
having a certain refrangibility. This examination is of especial 
interest in the detection of color-blindness. (See page 481.) 

Method of Holmgren. — This consists in testing the power 
of a person to match various colors, conveniently used in the form 
of colored yarns. The test colors, viz. : light green, rose or pur- 
ple, and red, are placed before the patient, who is required to 
select similar colors from a mass of colored yarns in which a 
great number of tints are associated in a confused mixture. 

Method of Thomson. — Dr. William Thomson has devised 
the following arrangement of the yarns : The set consists of a 
large green and a large rose test-skein, and forty small skeins, 
each marked with a bangle having a concealed number, extending 
from one to forty, placed in a double box, so arranged as to keep 
the two series apart. 

The large green skein being placed near by, the small skeins 
from one to twenty are placed in good daylight, and the employe, 
under examination is directed to select ten shades of the same color 
as the test-skein. One with normal vision will choose promptly 
the ten greens with odd numbers. 



EXTERNAL EXAMINATION OF THE EYE. 71 

A color-blind person will hesitate, and his selections will contain 
some even numbers, and the confusion-colors will be shades of 
brown, etc, containing some red, or -hades of gray, and will 
indicate the color-defect. These figures are to be recorded on 

a blank, and the twenty skeins are to be removed. The large 
rose skein is then used, and the examination repeated in like 
manner with skeins numbered from twenty-one to forty, and 
the result recorded. The confusion-skeins, which have even 
numbers, are blue, green, and gray. From the selections made 
by the man found color-defective by the green test, we are able 
to decide the character of his color-blindness. Those selecting 
blues are red-blind, those taking greens and grays are green- 
blind, according to the nomenclature of Holmgren. There are 
ten roses and ten confusion-colors in the second series. 

(1 .) The Lantern-Test. — The question is often asked whether, 
in the examination of sailors and railroad employes for the detec- 
tion of color-blindness, the tests are not of such a character that 
men, for all practical purposes safe in their chosen occupations, are 
rejected. In other words, it has sometimes been believed, and 
often stated, that the tests were so searching that valuable men 
were discarded, although exhibiting only very slight degrees of 
deficiency in the color-sense, too slight to render them unfit for 
railway service. 

The detection of color-blindness from a practical point of view 
has been a subject of considerable study at the hands of F. W. 
Edridge-Green, who believes that the exclusion of dangerous 
persons only is essential, and that the possession of slight de- 
grees of color-blindness may be permitted to be passed by, as, 
for all practical purposes, their subjects are normal-sighted. He 
has devised an apparatus which consists of a lantern and twelve 
slides. Six slides contain colored glasses (standard red, yellow, 
pure green, standard green, blue, and purple), and six contain 
modifying glasses, that is, glasses which are ground, ribbed, and 
composed of four thicknesses of a special kind of neutral glass. 
The object of the test is to ascertain whether the candidate under 
trial can discriminate between red, green, and white lights. To 
prevent guessing, the colors before-mentioned, other than red and 
green, are employed. 



72 DISEASES OF THE EYE. 

Dr. Edridge-Green thus describes the application of bis method : 
The candidate should be seated at a distance of fifteen feet from 
the lantern. He should be asked to name the color of the light 
produced by a colored glass alone, or in combination with the 
modifying glasses. A candidate should be rejected : (1) If he 
calls the red green, or the green red, under any circumstances ; 
(2) if he calls the white light, under any circumstances, red or 
green, or vice versa; (3) if he calls the red green, or white light 
black, under any circumstances. 

A candidate who makes mistakes other than those mentioned 
should be put through a very thorough examination. This ex- 
amination can be made by what Dr. Edridge-Green calls the 
classification test, which he intends for scientific purposes, and 
which consists in a series of test and confusion colors, the candi- 
date being required to match the test colors. This examination 
apparently differs only in the method of its application from 
such as are well known. 

(2) The Pseudo-isochromatic Plates of Stilling. — These con- 
sist of a series of plates (ten in number), each plate containing 
four squares filled by small, irregular, colored spots, among which 
other spots in a confusion color, made to conform to an Arabic 
figure, are placed. The test-plate is held in a good light, and 
the examiner requires the subject to distinguish the tracings. 
These plates are said to be of practical use. 

Accommodation has been defined to be those changes in the 
optical adjustment of the eye effected by the ciliary muscle 
(Schweigger), and in practice is measured by finding the nearest 
point at which fine print can be clearly deciphered. The type 
usually adopted is that known as Snellen's 0.5, or Jager's 1. 

In order to study the phenomena of accommodation the stu- 
dent should record : 1. The nearest point of perfectly distinct 
vision attainable with the smallest readable type, or the punetum 
proximv/m, (abbreviated p.p., or simply p.). 2. The farthest point 
of distinct vision, or punetum remotum (abbreviated p. v., or sim- 
ply r.). 3. The range, amplitude of accommodation, or the expres- 
sion of the amount of accommodative effort of which the eye is 
capable. This is expressed in the number of that convex lens, 



EXTERNAL EXAMINATION <>!' THE EYE. 



73 



placed close to the cornea, whose focal length equals the distance 
from the near point to the cornea, and which gives rays a direc- 
tion as if they had come from the far point; thus, if the near 
point be 7 cm., the lens which expresses the amplitude of ac- 
commodation is + 14 D. — - = 14. 4. The region, or the 
space in which this is available. 5. Relative accommodation, or 



O. D. 

Tlift etou»be*rt adapted fbr Htho- 
gruphic purpose! is a calcarvoua 
plato found on tho banks of the 
3>r\nube, in Bavaria, tho finest 
"being found near Jtfunich, A 
good Btona is porous, yet brittl*- 
of a palo yoUowlsh drub, and 
sometimes of a pray nouti-al trnt 
The stones aro formed in^o slabs 
from one and a half to three 
inches in thickness* To prepare 
them for use. two etonea aro put 
&C9 to face with eome fino eifted 
sand between them, and then are 
rubbed together with, a, circular. 



Fig. 32. 



.50M. 



o. s. 

Thfl stone "bent adapted fnr^Jitho-.' 
gmyhic purpose* is a caloareoua 
slate found on the banks of the 
Danube, in Bavaria, the finest 
Doing found near Munich. A 
good stone is porous, yet brittle, 
of a pale yellowish drab, and 
sometimes of a pray neutral tint 
The 6tones are formed into slabs 
from one and a hall" to three 
inches in thickness. To prepare 
them for use. two 6tone3 are put 
face to feoe -with some fine sifted 
Band between them, and then are 
rubbed together with a circular. 



O. D. 

The artist completes a 
chalk drawing upon a 
grained stone as he 
■would make one •with 
pencil or chalk upon, 
paper. If -while in this 
state a wet sponge ia 
passed over the face 
of the stone, the draw- 
ing -will rub oiE To 



•7SM- 



O. S. 

The artist completes a 
chalk drawing upon a 
grained stone as lie 
would make one with 
pencil or chalk upon 
paper. If while in this 
state a wet sponge ia 
passed over the fiice 
of the stone, the draw- 
ing -will rub of£ To 



Type for testing accommodation. 



that independent portion of this function which can be exercised 
without alteration in a given amount of convergence, and is 
divided into a negative portion, or that portion which is already 
in use, and a positive portion, or that portion which is not in use. 
(See also page 44.) 

Mobility of the Eyes. — This is tested by causing the patient 
to follow with his eyes, the head remaining stationary, the move- 
ments of the uplifted finger which is directed to the right, to the 
left, upward and downward. Both eyes must be observed, and 
note made of any lagging in their movements, or of the failure of 



74 DISEASES OF THE EYE. 

either eye readily to turn into the nasal or temporal canthus. At 
the same time the relation of the movements of the upper lid to 
those of the eyeball is recorded. The attention of the patient 
must be centred upon the moving finger, and allowance should 
be made for the imperfect mobility of highly myopic eyes. Any 
asymmetry of the skull, or difference in the level of the two 
orbital margins, may be observed, because such conditions are not 
infrequently associated with ametropic eyes, especially when the 
two eyes possess great inequality in refractive conditions. 

Balance of the External Eye Muscles. — Under normal condi- 
tions perfect equilibrium of the external eye muscles is present, but 
preponderance, for example, of the power of the external recti 
(insufficiency of the internal recti), or vice versa, produces a ten- 
dency to divergence or convergence, which, however, is overcome, 
with preservation of binocular vision, in spite of the disturbed 
equipoise. This condition was named by Von Graefe dynamic 
strabismus. 

In order to ascertain the condition of the ocular muscles we 
employ the following tests : — 

(1) Approach the finger to within a few inches of the eyes, 
which are steadily fixed upon its tip, and note if a convergence 
to a distance of 8 cm. (3| inches) is attainable. If, before this 
point is reached, one eye deviates outward, weakness of the 
interni is present, the eye possessing the weaker internus usually 
being the one which exhibits the deviation. This test is a rough 
one, and valuable chiefly for ascertaining which of the interni is 
the weaker. 

(2) Require the patient to fix upon a fine object, as a pin- 
point, held below the horizontal, 20 or 25 cm. from the eye, and, 
in order to remove the control of binocular vision, cover one eye 
with a card or the hand, and observe whether the eye under cover 
deviates inward or outward, and returns to fixation when the cover 
is removed. 

If the patient fixes the object accurately, and the manipula- 
tions of covering and uncovering first one eye, and then the 
other, are rapidly performed, trustworthy results will be obtained. 
In general terms, each millimeter of movement of the devi- 



EXTERNAL EXAMINATION OF THE EYE. 10 

ating eye corresponds to 2° of insufficiency as measured by 
prisms. In the case of the interni, it' the covered eye moves in 

to fix, with several distinct impulses, each impulse should be mul- 
tiplied into the foregoing result. | Randall.) 

(3) Produce vertical diplopia with a prism, and test the func- 
tion- of the lateral muscles at a distance of 6 metres. 

A small flame is placed against a dark background at 
6 metres from the patient, and on a level with his eyes. In 
an accurately adjusted trial frame, a prism of 7° is inserted, 
base down, before one eye, for example the right. Vertical 
diplopia is induced, and the upper image belongs to the right 
eye. If the flames stand, one directly over the other, there is no 
inclination to divergence or convergence. If the upper image 
stands to the left, there is weakness of the interni; if to the 
right, of the externi. That prism placed with its base in or out 
before the left eye, according to circumstances, which brings the 
two images into a vertical line, measures the degree of the devia- 
tion. (Compare pages 77-79.) 

Thus the presence or absence of lateral insufficiency is de- 
termined. 

(4) Produce lateral diplopia, and test the functions of the ver- 
tical muscles at a distance- of 6 metres. 

The patient is seated as before, and a prism of sufficient 
strength to induce homonymous diplopia is placed before one 
eye, for example, the right, i. e., with its base towards the nose. 
If the images are on the same level, no deviating tendency is 
present. If the right image rises higher than the other, the 
visual line of the right eye tends to be lower than that of its 
fellow, and there is insufficiency of the vertical muscles. That 
prism, placed with its base down before the left eye, which 
restores the images to the horizontal level, measures the degree 
of deviation. (Compare pages 79, 80.) 

(5) Produce vertical diplopia, and test the functions of the 
lateral muscles at the ordinary working distance, or 30 cm. 

For this purpose it is customary to employ the equilibrium * 
of Von Graefe, in which a card having upon it a large dot, through 
which a fine line is drawn, is held 25 or 30 cm. from the eyes, 



76 DISEASES OF THE EYE. 

diplopia being induced by means of a prism of 10° or 15°, base 
up or down, before one eye. A more accurate test-object is a 
small dot and fine line, or a single word printed in fine type, 
requiring accurate fixation and a sustained effort of accommoda- 
tion. If, the prism being placed base down before the right eye, 
the images stand exactly one above the other, equilibrium is evi- 
dent ; if the upper image (image of the right eye) stands to the 
left of the lower image, there is crossed lateral deviation; and 
that prism, placed before the left eye with its base towards the 
nose, which restores the images to a vertical line, measures the 
tendency to divergence, exophoria, or insufficiency of the internal 
recti. If the upper image stands to the right of the lower, there 
is homonymous lateral deviation; and the prism, placed before 
the left eye with its base towards the temple, which restores the 
images to a vertical line, measures the tendency to convergence, 
esophoria, or insufficiency of the external recti. 

(6) Ascertain the power of adduction, abduction, and sursum- 
duction by finding the strongest prism which the lateral and 
vertical muscles can overcome (see page 509). 

Beginning with adduction, find the strongest prism placed 
before one eye, with its base towards the temple, through which 
the flame still remains single. The test should begin with 
a weak prism, the strength of which is gradually increased until 
the limit is ascertained. This varies from 30° to 50°. 

In like manner abduction is tested, the prism now being turned 
with its base toward the nose ; 6° to 8° of prism should be 
overcome. The ratio between adduction and abduction should 
be 6 to 1 (Stevens), i. e., if adduction is 48°, abduction should 
be 8°; but according to Risley, in carefully corrected or emme- 
tropic eyes, the ratio is 3 to 1. 

Sursumduction, or the power of uniting the image of the candle 
flame, seen through a prism placed with its base downward before 
one eye, with the image of the same object as seen by the other 
eye, is ascertained by beginning the trial with a weak prism, |° 
or 1°, and gradually increasing its strength. The limit is usually 
3°, but may be as high as 8° or 10°. 

If the eyes of the patient under examination are ametropic, 
the proper correcting lenses should be placed before them, and 



EXTERNAL EXAMINATION OF THE EYE. 77 

the examination for the various forms of insufficiency made 
through this glass. It is, moreover, exceedingly important that 
the correcting glass should be accurately centred. Any failure of 
this, in a lens of considerable thickness, would induce a prismatic 
effect, which would utterly preclude accurate determination of the 
muscular conditions, (.specially of the vertical muscles, where the 
search, for fractions of a degree of deviation are sometimes 
necessary. If the muscular examinations have been undertaken 
as part of a routine preliminary examination of an eye, they 
should be repeated after the refraction has been accurately de- 
termined, and, if anomalous, corrected. 

Practically, all of the examinations for muscular errors can be 
made with a series of prisms and a trial frame, but they are 
facilitated by the use of certain instruments of precision, espe- 
cially some form of Herschel or revolving prism, the one devised 
by Risley being the best. The latter consists of two prisms, 
superimposed with their bases in opposite directions, constituting 
a total value of forty-five degrees. They are mounted in a cell 
which has a delicately milled edge, and fits in the ordinary trial- 
frame. The milled edge permits convenient turning in the 
frame, so that the base or apex of the prisms can be readily 
placed in any desired direction. The prisms are caused to rotate 
in opposite directions by means of a milled screw-head, project- 
ing from the front of the cell. With this rotary prism the 
strength of the abducting, adducting, and supra- and infra- 
ducting muscles can be measured. If the rotary prism is placed 
before the left eye with the zero mark vertical, and the screw 
turned to the right or left, it will cause the base of the resulting 
prisms to be either inward or outward, that is, toward the 
nose or temple, as may be desired ; or it may be placed with 
the zero mark horizontal, and the base turned upward or 
downward. 

One of the simplest tests of the ocular muscles is the obtuse- 
angled prism of Maddox. This is composed of "two weak 
prisms of three degrees, united by their bases. On looking 
through the line thus formed, at a distant plane, two false images 
of it are seen, one higher and one lower than the real image 
seen by the other eye, the position of which, to the right or the 



78 



DISEASES OF THE EYE. 



F JO - 33. left of the line between the false images, 

indicates the equilibrium of the eye. A 
faint band of light, of the same breadth as 
the two false images, is seen extended be- 
tween them." (Fig. 33.) The answers of 
the patient may be materially assisted by 
placing a red glass before one eye, and thus 
tintiug the real image. If this stands di- 
rectly in the centre between the two false 
images, all forms of insufficiency are elimi- 
nated ; if it stands to the right or to the 
left, there is insufficiency either of the ex- 
ternal or of the internal recti ; if it stands 
above or below the centre, or is fused with 
either the upper or the lower image, there 
is insufficiency of the superior or inferior 
recti. 

Insufficiency of the oblique muscles (cy- 
clophoria), according to Savage, may be de- 
tected " by placing a Maddox prism, with its 
axis vertical, before one eye, the other being 
covered, which regards a horizontal line on 
a card eighteen inches distant. This line 
appears to be two, each parallel with the 
other. The other eye is now uncovered, 
and a third line is seen between the other 
two, with which it should be parallel. 
Want of harmony in the oblique muscles 
is shown by want of parallelism of the 
middle with the other two lines, the right end of the middle 
line pointing toward the bottom and the left end toward the top 
line, or vice versa, depending upon the nature of the case." l 

The rod test, also designed by Maddox, depends upon the 
property of transparent cylinders to cause apparent elongation of 
an object viewed through them, so that a point of light becomes 
a line of light so dissimilar from the test-light that the images 

1 Much doubt has been cast upon the accuracy of this test by F. B. Eaton, who 
considers the phenomenon a physiologic one. Consult Journal of the American 
Medical Association, September, 1894. 




Position of the images as 
seen through the obtuse- 
angled prism of Maddox 
(Randall). 



EXTERNAL EXAMINATION OF THE EYE. 



79 



are not united. It may be suitably employed by having mounted 
in a cell, which will fit in the trial frame, a transparent glass rod 
colored red, f of an inch long, and about the thickness of the ordi- 
nary stirring roil used by chemists, neatly modified by Jackson. 

The examination for horizontal deviation is thus described : 
"Seat the patient at 6 metres from a small flame, placed against 
a dark background, and place the rod horizontally before one eye. 
If the line passes through the flame, there is orthophoria (equi- 
poise), as far as the horizontal movements of the eyes are concerned. 
Should the line lie to either side of the flame, as in most people 
it will, there is either latent convergence or latent divergence ; 
the former, if the line is the same side as the rod (homonymous 
diplopia) ; the latter, if to the other side (crossed diplopia)." 




Maddox's rod test for horizontal deviation. The rod is before the right eye. A. 
The line passes through the flame — orthophoria. B. The line passes to the right 
of the flame — latent convergence, or esophoria. ft The line passes to the left of 
the flame — latent divergence, or exophoria. 

In order to test the vertical deviation, the rod is placed verti- 
cally before the eye ; a horizontal line of light appears, and the 



80 



DISEASES OF THE EYE. 



patient is asked if the line passes directly through the flame, or 
if it appears above or below it. The following rule, quoted from 
Maddox, will suffice to indicate the " hyperphoria" eye : " If 
the flame is lowest, there is a tendency to upward deviation of 
the naked eye ; if the line is lowest, of the eye before which the 
rod is placed." 1 

The measurement of the extent of the deviation may be made 
in the ordinary way, by finding that prism, placed before the 
naked eye (preferably with the rotary prism of Risley), which 
brings the line and flame together. 





Fig. 35. 


A, 


B. 


^1 aU H 


mm 




mmk. Mi.^mm 




W* j pH 


■LJi 


w mmm W m 




Maddox's rod test for vertical deviation. The rod is before the right eye. A. 
The line passes through the flame— orthophoria. B. The line passes below the 
flame. The upper image belongs to the left eye — right hyperphoria. ft The line 
passes above the flame. The upper image belongs to the right eye — left hyper- 
phoria. 

In order to avoid the awkwardness of the phraseology " in- 
sufficiency of the internal recti, etc," and at the same time more 
accurately to describe the muscular anomalies, the following ter- 
minology has been introduced by Dr. George T. Stevens, and 
has received a deservedly wide acceptation : — 

"The condition in which all adjustments are made by muscles in a 
state of physiological equilibrium is called orthophoria. 



1 Dr. Swan M. Burnett substitutes for the Maddox rod a 6 D cylinder. 



EXTERNAL EXAMINATION OF THE EYE. 81 

Disturbances of equilibrium are known as heterophoria, or insuffi- 
ciencies of the ocular muscles. 

The deviating tendencies of heterophoria may exist in as many 
directions as there are forces to induce irregular tensions. 

The following system of terms is applied to the various tendencies 
of the visual lines : — 

I. Generic Terms. — Ortiiophoria : A tending of the visual lines in 
parallelism, Heterophoria: A tending of these lines in some other 
way. 

II. Specific Terms. — Hetrophoria may be divided into — 

1. Eaophoria : A tending of the visual lines inward. 

2. Exophoria: A tending of the lines outward. 

:'.. Hyperphoria (right or left): A tending of the right or left visual 
line in a direction above its fellow. 

This term does not imply that the line to which it is referred is too 
high, but that it is higher than the other, without indicating which 
may be at fault. 

III. Compound Terms.— Tendencies in oblique directions may be 
expressed as hyperesophoria, a tending upward and inward ; or hyperexo- 
phoria, a tending upward and outward. The designation 'right' or 
'left' must be applied to these terms." 

Power of Convergence. — In order to determine the maximum 
of convergence, an instrument, known as an opMhalrmy-dynamo- 
meter, may be employed. The one devised by Landolt consists of 
a metallic cylinder, blackened on the outside, placed over a candle 
flame. The cylinder contains a vertical slit, 0.3 mm. wide, covered 
by ground glass. The luminous vertical line thus produced is 
the object of fixation. Beneath the cylinder is attached a tape 
measure graduated on one side in centimetres, and on the other in 
the corresponding number of metre-angles. The fixation object is 
gradually approached in the median line towards the patient, 
until that point where double vision occurs is reached, or the 
nearest point (punctum proximum) of con vergence, and the distance 
iu centimetres read from one side of the tape, and the correspond- 
ing maximum of convergence in metre-angles on the other. 

The minimum of convergence may also be ascertained with 
the instrument, but when this is negative it is determined by 
finding the strongest abducting prism which will not cause 
diplopia while the patient is fixing a candle flame at 6 metres. 
If the number of the prism is divided by 7, the quotient will 
approximately give in metre-angles the amount of deviation of 
6 



82 DISEASES OF THE EYE. 

each eye when the prism is placed before one. The amplitude 
of convergence is equivalent to the difference between the maxi- 
mum and minimum of convergence. 1 (See metre-angles, page 
54.) 

The Field of Vision. — "When the visual axis of one eye is 
directed to a stationary point, not only is the object thus " fixed" 
alone visible, but also all other objects contained within a given 
space, which is large or small, in proportion to the distance of 
the fixation point from the eye. This space is the field of vision; 
and the objects within it imprint their images upon the peri- 
pheral portions of the retina, or those which are independent of 
the macula lutea. In contradistinction to visual acuity and 
refraction, which pertain to the macula in the act of direct vision, 
the function of sight capable of being performed by the rest of 
the retina is called indirect vision. 

The limits of the visual field may be roughly ascertained in 
the following manner : Place the patient with his back to the 
source of light, and have him fix the eye under examination, the 
other being covered, upon the centre of the face of the observer, 
or upon the eye of the observer which is directly opposite his 
own, at a distance of two feet. Then let the surgeon move his 
fingers in various directions, midway between himself and the 
patient, on a plane with his own face, until the limits of indirect 
vision are determined, controlling at the same time the extent 
and direction of the movements by his own field of vision. This 
method suffices to discover any considerable limitation, and, in 
the event of such discovery, should be supplemented by a more 
exact procedure. 2 

If it is desired to have a map of the field not larger than 45 
degrees in extent, let the patient be placed twenty-five centimetres 
from a blackboard, which may be conveniently ruled in squares, 
and fix the eye under observation upon a small white mark. The 
observer then moves the test object, a piece of white paper one 
centimetre square, affixed to a black handle, from the periphery 

1 Landolt's Refraction and Accommodation of the Eye. 

2 In the systematic examination of the eye, it is not usual to map out the 
field of vision before an ophthalmoscopic examination has been made ; but 
the description of the methods is conveniently placed here. 



EXTERNAL EXAMINATION OF THE EYE. 



83 



toward fixation, until tlw object is seen. If eight peripheral 
point- are marked, and afterwards joined by a line, a fair map of 
the field of vision will be obtained. 1 



Fig. 36. 



T * S * 3 110 t S 3 4 e G 7 













































































































l" 


'"' 








\ 
\ 






















1 








1 




i 




















1 




+■ 






,' 


\ 
1 




















X 

X 


* 






/ / 




1 
I 




















*« 


*.. 


V- 


-- J 




r 
1 













































































































mute 

J5/«c«- - 

Red 

Limits of the normal field for white, blue, and red, transcribed upon a blackboard 

(after Xorris). 

Beyond 45 degrees this method ceases to be accurate, because 
on a flat surface the object is too far away from the eye ; rays 
perpendicular to the visual line coming from a peripheral object 
W< »uld be parallel to the blackboard, and could not arise from it, 
or any object passed across its surface (consult Fig. 39). 

1 The value in degrees of the squares on the blackboard may be ascertained 
by the following table, provided the eye is placed exactly at 25 centimetres 
from the fixation point : — 

2.2 centimetres = 5 degrees in the perimeter semicircle. 



4.4 

6.7 
9.1 
11.7 
14.4 
17.5 
21 
25 
30 
36.7 
43.3 



= 10 
= 15 

= 2o 

= 30 
= 35 
= 40 
= 45 
= 50 
= 55 
= 60 



84 



DISEASES OF THE EYE. 



Hence, the investigation of the periphery of the retina requires 
the use of an instrument, known as a perimeter. This consists 



Fig. 37. 



oooo 




Perimeter. — The examination may be made with the carrier which moves along 
the semicircle, or the test objects may be carried along this by means of dark 
discs attached to a long handle, each disc containing in its centre the test object. 
The patient's chin is placed in the curved chin-rest; the notched end of the up- 
right bar is brought in contact with the face, directly beneath the eye to be ex- 
amined, which attentively fixes the centre of the semicircle. The other eye should 
be covered, preferably with a neatly adjusted bandage. The record-chart is in- 
serted at the back of the instrument, and, by means of an ivory vernier, the ex- 
aminer is enabled to mark exactly with a pencil the point on the chart, corre- 
sponding to the position on the semicircle, at which the patient sees the test object. 
The various marks are then joined by a continuous line, and a map of the field is 
obtained (see Fig. 38). 



essentially of an arc marked in degrees, which rotates around a 
central pivot, that at the same time may be the fixing point of 



EXTERNAL EXAMINATION OF THE EYE. 85 

the patient's eye, which is placed 30 centimetres distant (the 
centre of curvature of the perimeter arc), or the eye may be directed 
upon a porcelain button on a bar, placed 15 degrees from the 
centre, to the left, if the right eye is to be examined; vice versa, 
if the left is under observation. The test object, one to two centi- 
metres in diameter, affixed upon a carrier, is moved from without 
inward, and the point noted in each meridian where it is recognized. 
The result is transcribed upon a chart, prepared by having ruled 
upon it radial lines to correspond to the various positions of the 
arc, and concentric circles to note the degrees. 

Many ingenious instruments have been devised, especially such 
as are self-registering, among which may be mentioned those of 
McHardy, Stevens, and Priestley Smith. 

The physiological limits of the form field, or, what is practi- 
cally the same thing, the field when this has been mapped with 
a square of white, are : outward, 90 ; outward and upward, 70 ; 
upward, 50 ; upward and inward, 55 ; inward, 60 ; inward and 
downward, 55 ; downward, 72 ; downward and outward, 85. 1 

These measurements, which vary within normal limits, trans- 
cribed upon a chart, produce the following figure. (Fig. 38.) 

From this it is evident that the field of vision is not circular, 
being greatest in extent outward and below, and most restricted in- 
ward and above. This restriction is partly due to the presence of 

1 Bjerrum proposes an addition to the usual method of examining the field of 
vision, a description of which is condensed from Berry's translation of the 
original paper : The addition consists in making use of white objects which 
subtend a very small visual angle. The examinations are made at a distance 
of two metres, using a large black screen, two metres in breadth, which can 
be let down from the ceiling to the floor. At this distance the blind spot (see 
page 90) instead of measuring 2.5 cm., as on an ordinary perimeter, measures 
20 cm. in diameter ; and everything else is in the same proportion. 

The objects used by Bjerrum are small circular disks of ivory, fixed on the 
end of a long, dull black rod. They vary from 10 to 1 mm. in diameter. 
The examination is begun in the ordinary manner (at 30 centimetres), with 
the 10 mm. disc, and then continued at 2 metres distance with a 3 mm. disc. 
In the first case, the visual angle approximately is 2°, in the second 5'. 
The normal boundaries in the first instance have been given ; in the second 
they are 35° outwards ; 30° inwards ; 28° downwards ; and 25° upwards. 
Small concentric limitations are unimportant, but the method is valuable in 
finding sector-shaped defects, irregular limitations, and scotomata (page 89). 



86 



DISEASES OF THE EYE. 



the edge of the orbit and the nose, and partly, as Landolt has pointed 
out, because the outer part of the retina is less used than the 



Fia. 38. 




Diagram of the field of vision for white (1 centimetre square test object), trans- 
cribed upon a perimeter chart. 

inner, and its functions, therefore, are less developed. Hence, as 
each portion of the field corresponds to the opposite portion of 
the retina, the inner part is smaller than the outer. To avoid the 
influence of the physical obstacles afforded by the cranial bones, 

Fig. 39. 




Projection of the field of vision upon the semicircle of a perimeter. (Fuchs.) 

the eye should be made to fix an object, in each meridian, 30° in 
the direction opposite to that under measurement. 

The accompanying diagram, taken from Fuchs, illustrate- the 



EXTERNAL EXAMINATION OF THE EYE. 



-7 



projection of the field of vision of the eye, A, upon the semicircle 
of the perimeter /'. Tin- extends from 65°, on the nasal side, to 
90° <>n the temporal Bide, and corresponds to the points e and d 
of the retina, which indicate the anterior border of the sensitive 
retina, reaching farther forward on the nasal than on the temporal 
side. It also illustrates thai the field of vision cannot be recorded 
Dp to its temporal limits on a plane surface (see page s.'li. 

Binocular Field of Vision. — The field of vision for each 
eye having been defined, it remains to point out that the field of 
vision which pertains to the two eyes, or that portion in M'hich 
binocular vision is possible, constitutes only the area where the 
<entral and inner parts overlap. This is evident from the dia- 
gram. The continuous line L bounds the field of vision of the 
left eye, and the dotted line R the visual field of the right eye. The 
central white area corresponds to the portion common to both 
eyes, or to that area in which all objects are seen at the same time 
with both eyes; the shaded areas correspond to the portions in 
which binocular vision is wanting. In the middle of the white 
area lies the fixation point/, and on each side of it the blind 
spots of the right and left eye, r and I. 

Fig. 40. 




Binocular field of vision. (Moser.) 



Having thus determined the limits and continuity of the visual 
field, the functions of the peripheral parts of the retina in regard 
to perception of colors, acuity of vision, and appreciation of light 
should be investigated. 

The color field is mapped in the manner described in connection 
with the general visual field, the squares of white in the carrier 



OO DISEASES OF THE EYE. 

of the instrument being replaced by pieces of colored paper one 
centimetre in diameter. 

The order in which the colors are recognized from without 
inwards is (1) blue, (2) yellow, (3) orange, (4) red, (5) green, 
(6) violet. In practical work, blue, red, and green are the colors 
employed, red and green being the color sense most usually 
affected in pathological cases. The colors are not correctly 
recognized when the object is first seen. Thus, yellow at first 
appears white ; orange, yellow ; red, brown ; green, white, gray 
or gray-blue; and violet, blue. The physiological limits of the 
color fields, which, like those of the general field, are subject to 
variations, correspond closely to the following : — 

Blue. Red. Green. 

Outward 80 65 50 

Outward and upward .... 60 45 40 

Upward 40 33 27 

Upward and inward .... 45 30 25 

Inward 45 30 25 

Inward and downward ... 50 35 27 

Downward ...... 58 45 30 

Downward and outward ... 75 55 45 

These, when transcribed upon a chart, are represented in Fig. 
41. 

The numbers represent the usual limits at which the color is 
recognized as such. They do not indicate its greatest intensity, 
which is perceived only at the fixation point. In order to avoid 
discrepancies, the character of the light, the nature and saturation 
of the color, and its distance from the eye should be carefully 
stated in describing examinations. 

The acuity of the vision of the peripheral parts of the retina 
may be tested with small squares of black paper, separated from 
each other by their own width, by noting the point in each meridian 
where they are recognized as separate objects ; or with gray patches 
of different intensity on a white ground (Ward Holden). 

The perception of light, according to the experiments of 
Landolt, is the most constant function of the healthy retina, and 
remains nearly the same throughout its surface, while the color 
and form-sense rapidly lessen toward the periphery. For prac- 
tical purposes, a candle flame passed along the arm of the peri- 



EXTERNAL EXAMINATION OF THE EYE. 



89 



meter may be used as a test-object; and, if vision is very de- 
fective, a second candle is made the point of fixation. Progres- 
sive diminution of light-sense from centre to periphery will be 
found if test-objects of varying luminous intensity, with the 
illumination of ordinary daylight, are employed. 

Pig. 41. 




Diagram of the field of vision for blue, red, and green. The outer continuous 
line indicates the limit of the form field ; the broken lines the limits of the color 
fields. 

The most frequent departures from those limits of the visual 
field assumed to be normal are general or concentric contraction ; 
contraction limited especially to one or the other side ; peripheral 
defects in the form of re-entering angles ; absence of one segment 
or quadrant ; and absence of the entire right or left half of the field. 

In addition to these defects, search should be made for dark 
areas within the limits of the visual field, or scotomata. These are 
di-tinguished as positive, when they are appreciated by the patient, 
and negative, when he is not conscious of their existence ; the latter 
are color scotomas, usually for red and green. They are further 
subdivided, according to their situation and form, into centra/, 
paracentral, ring, and peripheral. 

In every normal eye there is a physiological scotoma, corre- 
sponding to the position of the optic nerve entrance, which usu- 
ally may be found 15° to the outer side of, and 3° below, the 



90 DISEASES OF THE EYE. 

point of fixation ; the distance from fixation being greater in 
hypermetropic than in myopic eyes. This is known as Mariottefs 
blind spot. 

For the detection of scotomata, small test objects, white or 
colored, J of a centimetre square, are employed, which are moved 
in different directions from the point which the eye under obser- 
vation attentively fixes, and the spot marked where the object 
begins to disappear or change its color. The arm of the peri- 
meter is usually marked near the centre in half degrees for this 
purpose. All examinations around the centre of the field of 
vision, and hence the examination for scotomata, are readily 
made upon the blackboard. 

Berry urges that the ordinary test for scotomas be supple- 
mented by making an examination of the particular area of the 
field at a distance of 2 metres or more, so as to obtain a larger 
projection of the blind portion, and to be able to work with 
smaller retinal images, without necessitating the use of very small 
objects. 

Tension. — This term indicates the intraocular resistance, and 
is clinically demonstrable by palpating the globe with the finger 
tips. The middle and ring fingers are placed upon the brow of 
the patient, the tips of the index fingers upon the eyeball, and 
gentle to-and-fro pressure made, the eyes being directed down- 
ward. This pressure must be made in such a manner as not to 
push the ball into the orbit ; otherwise no information of its true 
resistance is obtained. The tension of one eye must always be 
compared with that of its fellow, and, in any doubtful case, the 
results may be contrasted with those obtained by examining an 
eye known to be normal in another patient of similar age. 

Normal tension is expressed by the sign Tn, and the departures 
from it by the symbols +?, + 1, + 2, + 3, and — ?, — 1 , — 2 ,— 3 ; 
the plus signs indicate increased, and the minus signs decreased 
resistance. In physiological experiments, various kinds of appa- 
ratus, constructed upon the principle of the manometer, are em- 
ployed, and for clinical purposes instruments known as tononiet< zrs 
have been devised. In practical work, however, sufficiently 
accurate data are obtainable by a careful use of the educated 
finger tips. 



EXTERNAL EXAMINATION OF THE EYE. 91 

Fir.. 42. 




Position of hands in determining the tension of an eyeball. 

Proptosis, or protrusion of the eye, may be caused by orbital 
diseases, tenotomy, paralysis of the ocular muscles, and Graves's 
disease ; while enlargement of the ball is the ' result of various 
conditions residing within the globe — myopia, intraocular tumor, 
and staphyloma. If the cause is unilateral, the resulting condition 
is asymmetrical ; and the two eyes may be compared by observing 
the relative positions of the apices of the cornea? with each other, 
and with the line of the brows. 

The eyeball is apparently sunken (Enophthalmos) in some cases 
of ptosis and in wasting of the orbital fat, and is diminished in size 
in high grades of hypermetropia and congenital failures of devel- 
opment. As Nettleship has pointed out, the amount of exposed 
sclera decides the apparent protrusion or recession of the eyeball. 

Position of the Eyes. — Instead of presenting parallel visual 
axes, one eye may be deviated inward, outward, downward, or up- 
ward, constituting one of the various types of strabismus (see 
page 509), a condition which may or may not be associated with 
diplopia (page 515). 



92 DISEASES OF THE EYE. 



CHAPTER III. 

REFLECTION. THE OPHTHALMOSCOPE AND ITS THEORY. 
OPHTHALMOSCOPY AND RETINOSCOPY. 

Reflection. — When light falls upon a polished surface, a por- 
tion of it is reflected. The angle of reflection is always equal 
to the angle of incidence. A polished surface, capable of reflect- 
ing light, is called a mirror. Mirrors are either plane, concave, 
or convex. 

A plane mirror reflects the rays falling upon it, so that they 
seem to come from a point as far back of the mirror as the object 
lies in front of it. It does not render the rays either convergent 
or divergent, nor does it lessen their convergence or divergence. 
Rays parallel before reflection are parallel after reflection. Rays 
convergent or divergent before reflection maintain the same rela- 
tion after reflection. In the figure, rays from the object B, 

Fig. 43. 




Reflection from a plane mirror. 

falling upon the mirror M, are reflected so that they enter the 
observer's eye, and seem to him to come from O' B f , situated as 
far back of the mirror as B is in front of it. The image is 
not inverted. The rays have a divergence from a point whose 
distance is equal to the sum of the distance from the light to 



REFLECTION. 93 

the mirror, and of the distance from the mirror to the eye. 
(Compare Retinoscopy. ) 

A concave mirror converges parallel rays of light to its princi- 
pal focus, and forms a real, inverted image in front of the mirror. 

Fig. 44. 




Reflection from a concave mirror. 

The principal focus of a concave mirror is equal to one-half 

the length of its radius of curvature, F = <r. 

The conjugate focal distance for any point greater than the 
principal focus may be found by the following formula : f, rep- 
resents the distance from which the rays diverge (the lamp or 
candle) ; j" is the distance of the conjugate focus. 

L L i 

f'~ F f 

This is understood by recollecting that F is the focus for 
parallel rays, and that the focus is the inverse of the reflective 
or catoptric power of the mirror. The rays which diverge from 

/' require — of catoptric power to render them parallel. This 
diminishes the catoptric power of the mirror to -=f 



94 DISEASES OF THE EYE. 

-p — ^ = 777, the focal length off", is the conjugate focal 

distance required. 

Examijle: The ophthalmoscopic mirror has a focus of 20 cm., its 
radius of curvature being 40 cm. A candle is situated at 30 centi- 
metres in front of it, and we wish to know the conjugate focal distance. 

F = 20 cm./' = 30 on, * - £ =*, £ = *>_ 1 _ ^ f _ 60 cm. 

The rays of the candle would be rendered convergent to a point 60 cm. 
in front of the mirror. The light being placed at a greater distance 
than the principal focus, the rays are convergent. 

A convex mirror renders parallel rays divergent as if they 
came from its principal focus, which is negative, situated behind 
the mirror, at a distance equal to one-half the radius of curva- 
ture. The image is erect and small. 

The conjugate focal distances for convex mirrors are obtained 
by the same formula as for concave mirrors, the sign — being 
prefixed to F&ndf". 

The cornea, by reflecting light, corresponds to a convex mirror, 
and in this relation is important in ophthalmometry. The prin- 
cipal focus of the corneal mirror is about 4 mm., the radius of 
curvature being 7.829 mm. The size of the image reflected from 
the cornea is proportional to the size of the object, as the focus 
of the corneal mirror, 4 mm., is to the distance of the object. 
A candle flame 20 mm. in diameter, situated at 100 mm., gives 
a corneal image whose size is found in this manner : Image : 20 : : 

4 : 100. - , as Image = .8 mm. If the radius of 

£\j 1 uu 

curvature is greater, the image is also greater ; if the radius of 
curvature is smaller, the image is smaller. By this means, cur- 
vature ametropia may be measured. 

The size of the corneal image is so very small that it would 
not be feasible to attempt direct measurement of it. If two 
candles, which are separated some distance, are employed as an 
object, each candle represents one extremity of the object. The 
size of the object is, then, the distance between the two candles ; 
the size of the image is the distance between the reflected images 
of the caudles. Suppose this distance to be 3 mm., and by means 
of a double refracting prism two images of each candle are seen ; 



THE OPHTHALMOSCOPE. 95 

if they are displaced by the prism exactly 3 mm., so that a straight 
line passes through all the images, two of them must overlie, as 
the images are 3 mm. apart. Small variations in curvature will 
now be manifest if the two images, which should overlie exactly, 
shoot past cadi other or tail t" come together. The change of 
form in the crystalline lens during accommodation is proven by 
this experiment. 

THE OPHTHALMOSCOPE. 

Ordinarily the interior of the eye is not visible. The retina 
is not sufficiently illuminated through a small pupil to send back 
rays which are perceptible. At times with a dilated pupil a 
red glare may be caught from an eye in an ordinary light by an 
observer at some distance, but no satisfactory details can be made 
out. 

In looking through the small aperture of the pupil, it is neces- 
sary for the observer to bring his eye close to the observed eye in 
order to discern the details of the eye-ground. In this position, 
no light can enter the patient's eye, because the observer's head 
intercepts it. If, now, a mirror be placed in front of the patient's 
eye, it will reflect the rays of a candle or lamp placed to the side 
of the patient and somewhat back of him, as if they came from 
in front of him. They will now enter the pupil and illuminate 
the interior of the eye. From the part thus illuminated rays 
return and enter the eye of the observer. This is what the 
ophthalmoscope accomplishes. 

In its most simple form (Helmholtz), it consists of three pieces 
of ordinary glass, set in a little frame. The amount of light 
reflected from one surface being- about -J* of the amount which 
falls on it, a combination of three surfaces is employed to in- 
crease the reflection. With this instrument the interior of the 
eye can be seen, but the illumination is weak, and the instrument 
has been superseded by a concave silvered mirror, w T hich by con- 
verging the rays increases the illumination. The credit of the 
invention of this instrument belongs to Helmholtz ; although, 
according to Brudenell Carter, the ophthalmoscope had been in- 
vented, four years before Helmholtz's instrument appeared, by 



96 DISEASES OF THE EYE. 

Mr. Charles Babbage. His instrument consisted of a concave 
perforated mirror adapted with lenses. Unfortunately, it had 
been entrusted to a practitioner who did not appreciate its value, 
and it remained unknown. 

The modern ophthalmoscope consists essentially of a concave 
silvered mirror for illuminating the eye, and of lenses for measur- 
ing and modifying its refraction. The mirror is perforated, and 
for convenience swings to either side, so that the obliquely incident 
rays may be reflected into the eye, without having to tilt the body 
of the instrument, and thus narrow the aperture and render the 
lenses astigmatic. A plane mirror, which can be substituted for 
the concave mirror, is a valuable addition to the instrument. 
The body of the instrument contains a disc carrying a number 
of lenses, which can be rotated in front of the sight-hole. The 
disc is the invention of Recoss. Most ophthalmoscopes contain 
two discs, which can be used either singly or in combination. 
This arrangement affords a series of lenses from .50 D to 24 D 
concave, and from .50 D to 23 D convex. The refractive errors 
of the eye are neutralized by these lenses, and thus the observer 
is enabled to view distinctly the details of the eye-ground in all 
forms of ametropia. A lens varying from 13 dioptres to 20 
dioptres accompanies the instrument for obtaining focal illumi- 
nation of the cornea and lens, as well as for the production of 
the image in the indirect method of ophthalmoscopy. 

Direct Method. — The rays from the concave mirror, somewhat 
converging, enter the pupil and are brought to a focus in the 
vitreous humor. After reaching their focus the rays diverge 
again and spread out on the retina into a circle of diffusion. 
The portion of the retina thus illuminated sends rays back 
again, which pass through the dioptric media of the eye and 
are refracted to its far point ; that is, if the eye is emmetropic, 
they emerge parallel and would meet at an infinite distance ; if 
the eye is myopic, they converge to their far point in front of 
the eye. If the eye is hypermetropic, they diverge from their 
far point back of the eye 

An observer's eye, in order to focus these rays, must be adapted 
to them. If the patient is emmetropic, the observer's eye must 
also be rendered emmetropic. If the patient is hypermetropic, the 



THE OPHTHALMOSCOPE. 



97 



observer must add a convex glass to his eye, or use his accom- 
modation, in order to make the divergent rays parallel. If the 
patient's eye is myopic, the emmetropic observer must place a 
concave glass before his eye to render the convergent rays par- 
allel. A hypermetropic observer might see distinctly the eye of 
a myopic patient, or a myopic observer might see the eye of a 
hypermetrope. In either case the hypermetropia must at least 
be as great as the myopia. 

In this method the observer sees the eye just as he would see 
an object through a convex glass, or simple microscope. The 
image of the eye-ground is a virtual one ; that is, it seems to be 
behind the eye. It is magnified and erect. 

The formation of the image in the direct method may be under- 
stood by the figure. 

Fig. 45. 




Formation of the image in the direct method of ophthalmoscopy. 



From the candle L the divergent rays falling on the mirror are 
rendered convergent. Passing through the refractive media of the 
eye they are rendered still more convergent, and come to a focus in 
the vitreous humor ; diverging again they form on the retina the illu- 
minated circle whose diameter is a b. If this eye is emmetropic, 
rays from the points x and y will pass out of the eye into the eye of 
the observer. All the rays from the point x will be parallel. Kays 
from the point y will also be parallel. No image is formed ; but the 
rays continue their course, and, entering the eye of the observer, come 
to a focus on his retiua at the points x' and y'. Kays from the point x 
in the patient's eye unite at the point x' on the observer's retina. In 
a similar manner rays from the point y in the patient's eye unite at 
the point y' in the observer's eye. These rays, projected backwards, 
seem to lie in their true position. 
7 



98 DISEASES OF THE EYE. 

Rays from the middle point m of the patient's eye unite on the middle 
point m of the observer's eye, and are projected backwards to the point 
from which they originated. The point <c, above m in the patient's 
eye, is represented by x in the observer's eye below the middle point 
m. The point y below m, in the patient's eye, is represented by y 
above m in the observer's eye. 

In hypermetropia, rays from x and y would be divergent, and the 
observer would have to render these rays parallel by a convex glass, 
or by using his accommodation. In myopia these rays would be con- 
vergent, and a concave glass would be required to neutralize their 
convergence and render them parallel. 

It is necessary here to point out an important fact in relation 
to the formation of an image. Divergent rays and convergent 
rays have been described, but always in relation to one point. 
It is now necessary to consider their meaning in reference to an 
image. 

An image is composed of a succession of points ; each one of 
these points represents a point in the object. From the point 
in the object one ray passes to the optical centre of the lens, or 
lenses, and maintains the same direction after passing through it. 
This ray is called the axial ray ; it passes to the corresponding 
point in the image. 

Other rays from the same point in the object diverge from the 
axial ray at various angles ; a bundle of these rays is called a 
pencil. The size of a pencil is determined by the diameter of a 
lens or the aperture of the pupil. The lens gives these unequally 
diverging rays a direction to a common point or focus. From 
each point in the illuminated part of the retina a pencil of rays 
falls upon the crystalline lens and cornea. The size of this pencil 
equals the diameter of the pupil ; to form an image each pencil 
of rays must be concentrated into one point. By diverging and 
converging rays we mean the relation the rays from each point 
bear to each other, not the relation of rays from different points. 

In the direct method the observer should place his eye close 
to that of the patient; otherwise only a very small portion of the 
fundus is visible. As the head is moved towards the right, ad- 
ditional portions of the retina towards the left are brought into 
view. If the head is moved towards the left, the portions of the 
eye-ground towards the right become visible. 



THE OPHTHALMOSCOPE. 99 

Size of the Image. — The details of the eye-ground are con- 
siderably magnified in the direct method of examination. The 
optic disc, which measures about 1.5 mm., appears under this 
method nearly the size of a 25-cent piece. This, however, is 
only relative to the distance it is projected. 

In the emmetropic eye the enlargement is found by the follow- 
ing formula : The distance of the retina from the nodal point 
(optical centre) of the eye is 15 mm. The observer projects the 
image which he sees to the point at which small objects are usu- 
ally held, say 250 mm. The enlargement of the disc is propor- 
tional to these two distances, 15 : 250 : : 1.5 mm. : 25 mm. 
16.6 = the enlargement. It is comparable to looking at the disc 
through a lens of 15 mm. focus, 66 dioptres. 

It is to be remembered that the farther this image is projected, 
the larger it appears. In hypermetropia the enlargement is less 
than this. In myopia, on the contrary, it is greater. 1 

Indirect Method. — In the indirect method of ophthalmoscopy 
a real, inverted image of the interior of the eye is obtained by 
means of a strong convex lens (object lens). 

This method is similar in principle to that of the compound 
microscope. The observer holds the object lens (a convex lens 
of about 20 dioptres) close to the patient's eye, and, placing a 
convex lens of 5 dioptres (eye-piece) behind the ophthalmoscope, 
throws the light into the pupil and moves his eye nearer to or 
farther from the patient's eye until he distinctly sees a vessel or a 
portion of the nerve. A real image of the eye-ground is formed 
by the object-lens at its focal distance in front of the eye. The 
observer sees this image, in which all the relations of objects are 
reversed. His eye is at a distance from the image equal to the 
focus of the lens in the ophthalmoscope, viz., 20 cm. The lenses 
of the eye and the convex lens form a combination like the objec- 
tive of a microscope. The lens which the observer places behind 
the ophthalmoscope represents the eye-piece of the microscope. 

The image being inverted, the lower portion of it corresponds 
to the upper part of the eye-ground. The right side of the image 

1 For the farther consideration of this, the student may consult Helmholtz. 
Physiolog. Optics, p. 216. 



100 DISEASES OF THE EYE. 

likewise corresponds to the left side of the eye. The upper and 
lower, as well as the right and left portions of the nerve, are re- 
versed. The image also has a contrary motion. If the observer 
moves upwards, the image moves downwards ; if the observer 
moves to the right, the image moves to the left. Consequently, 
the upper part of the image must be viewed if it is desired to see 
the lower part of the eye-ground, and the right side of the image 
if parts of the fundus to the left are to be examined. 

Explanation of the image in the inverted method: It must be 
remembered that the observer sees the same portion of the eye- 
ground, when he moves his head to the right or left, in the direct 
method as he does in the indirect method. Starting in the direct 
method with the disc in view, the observer moves his head to the 
right. He thus brings into view a portion of the retina to the 
left of the disc. The disc now moves out of the field towards 
the right, and disappears behind the right edge of the pupil. 
The image, therefore, moves with the observer. In the indirect 
method with the image of the disc in view, if the observer also 
moves his head to the right, he sees the image of the same por- 
tion of the retina as in the direct method ; but this being to the 
left of the disc, its image occupies a point to the right of that of 
the disc. (See Fig. 46.) The disc thus appears to have moved 
towards the left. The image, therefore, moves contrary to the 
observer's head. Movements in other directions are explained 
in the same way. 

The nerve appears much smaller than it does in the direct 
method, but a larger portion of the eye-ground is visible at one 
time. 

The formation of the inverted image in ophthalmoscopy is pro- 
duced in the following manner : — 

The ophthalmoscopic mirror is held at a considerably greater dis- 
tance from the patient than in the direct method. The rays from the 
candle come to a focus before reaching the eye, or object-lens. They 
then diverge, and, passing through the object-lens ?, are rendered 
convergent. After traversing the dioptric media of the eye, their con- 
vergence is increased, and once more they unite somewhere in the 
vitreous humor, from which point they diverge and form a circle of 
illumination on the retina. Their course, in passing from the candle 
until they reach the retina, is shown by the arrow-heads in the figure. 



THE OPHTHALMOSCOPE. 101 

A portion of the retina, a to b, represented by the arrow, forms an 
image, b' a', between the lens and the observer's eye, represented by the 
inverted arrow. Rays from the point a, on the upper part of the retina. 
pass out of the eye parallel to each other. After passing through the 

Fig. 46. 




Formation of the image in the indirect method of ophthalmoscopy. 

object-lens ?, they are rendered convergent and come to a focus at the 
point a' in the lower part of the inverted arrow. In the same way, rays 
from the point 6 on the lower part of the retina are parallel on passing 
out of the eye, but are rendered convergent by the lens I and come to 
a focus at a point b' in the upper part of the inverted arrow. It is this 
a rial image that the observer sees, and not the eye-ground of the pa- 
tient. Rays from this image are focused on the observer's eye, just as 
rays from the retina were focused in the direct method, i. e., the rays 
from the point a' are focused on a higher portion of the observer's 
retina, and rays from the point b' are focused on a lower portion. 
They are likewise projected back to the points in the image from which 
they originated. 

It is evident that, as the observer moves downwards towards o', he 
sees the image of the upper portion of the retina a. As he moves up- 
wards towards &', he sees the image of a lower portion of the retina in 
the direction o, since the highest portion of the retina forms the lowest 
portion of the image ; and, as the observer looks towards the lower 
portion of the image, in reality he sees, in this image, a higher por- 
tion of the retina. 

In hypermetropia and emmet ropia a convex lens is necessary 
to render the rays convergent. In myopia the rays emerge con- 
vergent, and the convex lens may be dispensed with in the 
higher grades, though it is still an advantage because it increases 
the area of the fundus visible at one time. 



102 DISEASES OF THE EYE. 

Size of the Image. — The enlargement of the image in this 
method is less than it is in the direct method. 

A real image of the eye-ground is formed by the convex object- 
lens held at its own focal length from the eye. In this position the 
size of the image in an emmetropic eye is represented by the fol- 
lowing proportion : The size of the disc is to the size of the image, 
as the distance from the retina to the nodal point (15 mm.) is to 
the focal length of the object-glass. If the lens has a focal 
length of 75 mm., the ratio is 15 : 75 ; the enlargement is then 
5 diameters. A lens of 60 mm. focns would equal an enlarge- 
ment of 4 diameters, 15 : 60. 

The observer will see this image under a higher angle in pro- 
portion as he comes closer ; it will then appear larger. To do 
this, he must either use his accommodation, or place a convex lens 
(eye-piece) behind the ophthalmoscope. When the eye-piece is 
used, a virtual image of the serial image, still more enlarged, is 
produced, just as in the compound microscope. If the object- 
lens is withdrawn farther than its focal length from the observed 
eye, the image in myopia becomes larger, in hypermetropia 
smaller, and in emmetropia remains the same. If the lens is 
brought closer to the eye, the image becomes smaller in myopia 
and larger in hypermetropia. 1 

Ophthalmoscopy. — The investigation of the deeper structures 
and interior of the eye by means of the ophthalmoscope may, 
therefore, be practised with (1) the direct, and (2) the indirect 
method. 

(1) The Direct Method (method of the erect or upright 
image). — The patient should be seated in a darkened room with 
his back to the source of illumination — an Argand burner beins; 
suitable — which is placed behind and to the side of his head, on 
a level with the ear, the face being in shadow, while the rays 
of light just fall upon the outer canthus of the eye. This will 
enable the observer to come quite close to the eye without inter- 
fering with the path of the illuminating beam. The surgeon sits 
at that side of the patient which corresponds to the eye under 
examination — for example, the right — his position being prefer- 

1 The section on Reflection and the Ophthalmoscope and its Theory, revised 
by Dr. Jackson, was prepared by Dr. Wallace for the first edition. 



OPHTHALMOSCOPY. 103 

ably on a slightly higher level than that of the subject. He 
now takes the ophthalmoscope in his right hand, looks through 
the Bight-hole with his right eye, at a distance of about 50 cm. 
from the observed eye (the convex border of the instrument 
being in contact with the concave margin of his brow), mean- 
while keeping the other eye open, and reflects the light into the 
right eye of the patient. If the left eye is to be examined, the 
ophthalmoscope is held in the left hand. 

If the patient looks directly into the light thus transmitted, 
the pupil — provided this is not dilated with a mydriatic — will 
contract, and no view is possible. He must hence be directed 
to turn the head slightly to the right, and gaze into vacancy in 
the farthest limit of the room, when the pupil will be seen illu- 
minated by a red glare — the reflection from the choroid coat — 
bright, if the pupil is large, and dull if it is small. No details 
of the fundus are as yet visible at this distance (50 cm.) unless 
a certain grade of myopia is present, or a considerable degree of 
hypermetropia. (See page 117.) 

The beginner should now practise keeping the light steadily 
in position, and may estimate the success of his endeavor by ob- 
serving the glare in the pupil. If this changes in color or dis- 
appears, the light has shifted from its proper position, because 
the examiner has failed to retain his elbow in close contact with 
his side, and allowed it to move outward and away from his 
body, the head meanwhile being bent to one or the other side of 
the vertical position it should assume in a direct line with that 
of the subject — feature to feature. This may be understood by 
observing the two accompanying illustrations. (See page 104.) 

Having gained control of the light, the observer gradually 
approaches the eye of the patient, taking care that the red glare, 
which is tinted slightly yellow on the nasal side marking the 
position of the optic papilla, remains unaltered, and comes as 
close as possible — within one inch, or even nearer. If the man- 
oeuvre has been successful, and the light directed slightly towards 
the nasal side, the most prominent feature in the eye-ground — 
the optic nerve — will come into view ; or a retinal vessel may 
first be manifest, and should be followed to the papilla as a 
stream would be to its source. 



104 



DISEASES OF THE EYE. 



Before proceeding to study the details of the fundus the student 
should make certain preliminary examinations. 

a. The Examination of the Cornea and Lens is made by 
placing a + 7 1) lens behind the mirror, and reflecting the light 
into the eye in the manner already described. 





Ophthalmoscopic examination. Method of the upright image. Observer and 
patient in the correct position. 

A foreign body on the cornea, a macula, a deposit on the poste- 
rior layer of the cornea, or an opacity in the lens appears as a 
black object against the red background, in contradistinction to its 
appearance in its true color under oblique illumination (page 62). 

At the same time the mobility of the iris should be tested, and 
an observation made as to whether the iris reacts promptly and 
evenly under the influence of the light directed into the pupil at 
various angles. 

b. The Examination of the Vitreous is made by reflecting 
the light from a distance of 30 cm. into the eye, while this is 
moved up and down, in and out. 

Vitreous opacities and detached retina are seen in the erect 



OPHTHALMOSCOPY. 



105 



position if the observer is sufficiently far away, because they are 
within liis range of accommodation. If he approaches closely, 
he must place behind the mirror a convex lens to bring them into 
focus, and should always use this method. 



Fig. 48. 





Ophthalmoscopic examination. Method of the upright image. Observer in 
an incorrect position. 

c. The Examination of the Transparent Media, with Refer- 
ence to the Position of Opacities. 1 — In order to detect the pres- 
ence of dense opacities, the concave mirror of the ophthalmoscope 
may be utilized. Faint opacities are best discovered by means of 
the plane mirror. The eye under examination should be moved 
in various directions, on the one hand, to bring into view opacities 
which have a lateral situation, and, on the other hand, to cause 
those opacities to rise upward which have sunk to the bottom of the 
vitreous chamber. Small opacities appear black ; larger opacities 
gray, or even white. 

In order to ascertain the position of an opacity, it is necessary 
to determine whether it is freely movable or fixed. In the first 
case, the opacity must be in the vitreous. In the latter case, if 
1 This paragraph is bassd upon Fuchs's description. 



106 DISEASES OF THE EYE. 

the opacity moves only with the movement of the eye, but not 
in a self-dependent manner, it probably is situated in the cornea 
or in the lens, but may be present in the vitreous in the form of 
a fixed opacity. 

In many instances the differential diagnosis can be made by 
means of oblique illumination. If this is not sufficient, the 
situation of an opacity is ascertained by means of its parallactic 
movement in relation to the border of the pupil. This can be 
understood by a reference to the figure. 

Fig. 49. 




Diagnosis of the situation of an opacity by the parallactic movement. (Fuchs.) 

In the eye A there are four opaque points which lie in different 
layers : (1) In the cornea ; (2) in the anterior capsule of the lens ; 
(3) at the posterior pole of the lens ; and (4) in the anterior layer of 
the vitreous. For the sake of simplicity, these are supposed to be 
situated in the optic axis of the eye. If the observer B looks directly 
forward into the eye, he will see these four points in the centre of the 
pupil P. If, now, the observing eye is moved from B to _B„ then the 
relative position of the points to the pupil will alter. Point 1 moves 
to the upper border of the pupil P, ; point ■_' retains unaltered its real 
position in the pupil ; points 3 and 4 approach the lower border of 
the pupil, 4 more than 3, corresponding to a deeper position. 

From this example the following rule may be deduced in order to 
find out the position of an opacity : The observer looks directly for- 
ward into the eye, and notes the position of an opacity within the pupil- 
lary space. Thereupon, while the patient keeps his eye entirely quiet, 
the examiner slowly moves to the side and observes if the opacity retains, 



OPHTHALMOSCOPY. 107 

or does not retain, the same position in the pupillary space. In the first 
instance, the opacity lies in the pupillary plane, upon or immediately 
under the anterior capsule of the lens. In the second instance, it is 
situated in front of or behind this plane ; in front of the plane if the 
opacity moves in a direction opposite to the movement of the ohserving 
eye, and behind the plane if the opacity moves in the same direction 
as the ohserving eye does. The quicker the change of position takes 
place, the farther is the opacity removed from the pupillary plane. 

Instead of proceeding in this manner, the observer may retain his 
position unaltered, and cause the patient to move his eye in various 
directions (see page 104). 

Having ascertained that the media are clear, and having ap- 
proached sufficiently close, the details of the fundus oculi are 
brought into view and studied seriatim. 

If either surgeon or patient is myopic, the necessary concave 
lens which corrects the error must first be placed in position ; 
while, if hypermetropia exists, the fundus is visible without the 
aid of a glass, provided the hypermetropia is not in excess of the 
power of accommodation. 

Failure to see any details, or seeing them as a blurred picture, 
naturally leads to the supposition that either myopia, or hyper- 
metropia beyond the power of accommodation, is present. Be- 
ginners, however, often fail to obtain an image of sharp definition, 
owing to inability to relax accommodation, and succeed in seeing 
the details clearly only through a concave glass. The power of 
relaxing the accommodation comes with practice. 

The optic nerve appears as a nearly round or slightly oval disc, 
situated towards the nasal side, varying in color from a gray- 
ish-pink to a more decided red, the tint being most marked upon 
the nasal half, while the centre is occupied by a whiter patch — 
the " light spot" — marking the position of the entrance and emer- 
gence of the retinal vessels. The general tint of the optic disc 
varies with the age and complexion of the patient, and with 
the intensity of the color of the surrounding eye-ground. 

The papilla is bounded by two rings. The outer one, dark- 
colored, usually incomplete, and sometimes entirely absent, or 
existing only as a slight crescent of pigment upon one or the other 
side, is the " choroidal ring" and represents the border of the 
choroid coat where this is pierced by the optic nerve. Within 
this is a faint white stripe, more distinct in elderly people, the 



108 



DISEASES OF THE EYE. 



"scleral ring" which indicates the rim of the sclerotic coat, or, 
according to Loring, the connective-tissue elements of the inner 
sheath of the nerve (" connective-tissue ring "). 

The central white patch may be noticeable only by contrast- 
ing it with the color of its surroundings, or it may be a dis- 
tinct excavation, occupying the centre of the disc, and having 

Fig. 50. 




V a 

Normal fundus of the left eye seen in the upright image. The vertically 
oval optic disc shows the entrance spot of the central vessels, somewhat to 
the inner side of its centre. The portion of the papilla which lies to the 
inner side of the vessel-eutrance is more darkly colored than the outer half; 
the latter portion shows, stretching outward from the entrance of the vessels, 
a light-colored spot, the physiological excavation, at the bottom of which are 
seen fine gray stipplings, the spaces of the lamina cribrosa. The papilla is 
surrounded by a white ring, the scleral ring, encircling which in a more periph- 
eral situation is an irregular, dark border, the choroidal ring, which, especially 
on the temporal side, is somewhat spread out. The central artery and the cen- 
tral vein divide out from the entrance spot in a superior and inferior branch. 
which appear somewhat lighter in this situation than in their further distribution 
in the retina, because they lie in the depth of the physiological excavation. The 
branches are still further divided on the papilla into a great number of twigs. Very 
fine twigs stretch from all sides towards the macula lutea, which itself is devoid 
of vessels, is somewhat more darkly colored, and in the middle of this a bright 
reflex, /, is visible. (Figure and description from Fuchs.) 

sharp borders, one of which often shelves slightly outward. 
This is the "physiological cup" and is the space left by the ra- 
diation of the nerve-fibres toward the retina, having a floor of 
white color, because it is composed of the interlacing opaque 



OPHTHALMOSCOPY. 109 

fibrous tissue, <>r lamina croorosa, which underlies the optic 
papilla. It is often stippled in appearance, owing to the lack of 

light reflected by the aon-medullated nerve-fibres which pass 
through the spaces of the lamina. According to Schoen, the 
so-called physiological excavations are due to dragging of the 
vaginal processes of the optic nerve and lamina cribrosa from 
over-exertion of the accommodation, and hence are found in 
adult eyes more commonly than in the eyes of children. They 
are practically always bilateral, although one may be larger than 
the other. Schweigger has traced hereditary transmission in 
some instances of large physiological excavation, but doubts if 
they are associated with any particular refractive condition of 
the eye. 

The Bloodvessels. — From this central spot the principal reti- 
nal arteries emerge, and into it the chief venous t ranks empty. 
Usually one venous and one arterial stem pass directly upward 
and downward, and on the edge of the disc, or a short distance 
from it, each divides into two branches. Sometimes this divis- 
ion has taken place in the axis of the nerve behind the lamina, 
and two arteries and two veins appear directly in the central 
opening of the papilla, or poms opticus. The arteries traverse 
the surface of the eye-ground, dividing dichotomously into nu- 
merous branches, and, passing above and below, spread in greater 
size and number over the temporal half of the retina, sending 
small branches toward the macula ; and in smaller size and less 
number over the nasal side. Fine branches arising from the 
central large trunks, or springing directly from the nerve, pass 
outward and inward, and also undergo numerous divisions. 

The veins pass over the eye-ground in the same general direc- 
tion as the arteries, and in close relation to them, emptying 
usually by means of two large branches into the centre of the 
disc. 

According to the situation of the vessels, they are named, re- 
spectively, upper and lower temporal artery and vein, upper and 
lower nasal artery and vein, and macular and nasal arteries and 
veins. 

The veins are dark-red in color, contrasting with the bright, 
natural blood-red color of the arteries. They are slightly tor- 
tuous, and larger than the arteries in the proportion of 3 to 2. 



110 DISEASES OF THE EYE. 

The difference in color between veins and arteries is most marked 
in the major branches. In the finer twigs, after four or five divi- 
sions, the distinction between arteries and veins is often only 
possible by tracing them to their source. 

Each vessel usually presents a double contour, owing to a 
bright stripe which passes along the centre, leaving a red line 
on either side. This so-called " light reflex" is a condensation by 
the refractive action of the blood column of the rays of light 
which have passed through the vessel from in front, and have been 
reflected back slightly from the posterior wall, but chiefly from 
the underlying tissues. 1 It is more marked upon the arteries 
than upon the veins, and, indeed, is often absent as the latter cross 
the disc, being visible in a minor degree when they lie at some 
distance in the retina. 

Pulsation does not occur in the retinal arteries of a normal eye. 2 
Spontaneous pulsation in the veins is a frequent phenome- 
non. Lang and Barrett found it in 73.8 per cent., Veasey in 
58.3, and the author in 62.1 per cent, of the cases examined. 
It may be produced by a slight pressure upon the globe. 
The spontaneous pulse is due to a communication of the ar- 
terial pulsation to the vein, as these vessels lie side by side 
iu the optic nerve, or may be explained by the theory of Don- 
ders, which stated that during the systole of the heart (diastole 
of the retinal arteries), an increased tension in the vitreous 
was communicated to the walls of the retinal veins, especially the 
larger ones, at their exit from the eye where the least resistance 
was offered, obstructing the flow of blood and compressing their 
lumen. The blood coming from the capillaries overcame this 
resistance, and the vessels regained their calibre, there being thus 
produced alternate collapse and distention. 

1 The cause of the light streak has stimulated much discussion, and was 
usually attributed to reflection from the anterior surface of the vessel wall, 
or the anterior surface of the hlood column, until Loring's investigation 
showed that the refraction of light was the chief cause of the phenomenon. 
Loring's conclusions have received experimental confirmation in the interesting 
research of Achilles E. Davis. Story rejects Loring's theory, and assumes that 
the reflex comes from the vessel walls. 

1 The phenomenon of arterial pulsation has been noted in perfectly normal 
individuals by Graefe, Jager, Donders, Becker, and Helfrich. 



OPHTHALMOSCOPY. 



Ill 



The student will more readily understand the relation of the 
Btructures which have been described by examining Fig. 51, 
which should also be studied in connection with the paragraphs 
which follow. 



Fir.. 51. 




a v 



mmw. 
sjsct n se " v n se p ar^ u 

A, ophthalmoscopic picture of the nerve-head. B, longitudinal section of the 
nerve-head. (Figure and description from Fuchs.) 



The upper figure, marked A in the illustration, represents the oph- 
thalmoscopic picture of the nerve-head. Slightly to the inner side of 
the centre of the papilla the central artery (a) is seen arising, and to 
the temporal side of this the central vein enters (v). To the outer or 
temporal side of the vein there is a physiological cup, at the bottom of 
which the gray stippling of the lamina cribrosa is visible. 

The nerve-head is surrounded by the white scleral ring — between c 
and d — and the dark choroid ring, at d. 

The lower figure, marked B in the illustration, represents a vertical 
section through the nerve-head ; the trunk of the nerve as far as the 
lamina cribrosa has been colored dark by Weigert's method, and re- 



11- DISEASES OF THE EYE. 

presents the medullated nerve-fibres (n). Between these the white 
spaces indicate the connective tissue septa (se). The nerve-trunk is 
inclosed in the pial sheath (p), the arachnoid sheath (ar), and the 
dural sheath (du). Between the sheaths the intra vaginal space re- 
mains free ; tins arises from the subdural space (scl) and the subarach- 
noid space (si), both of which end in a blind cul-de-sac in the sclera (s) at 
(e). The dural sheath terminates in the outer layers of the sclera (sa), 
the pial sheath in the inuer layers (si), which run crosswise through 
the optic nerve forming the lamiua cribrosa. The nerve in advance 
of the lamina is colored light, because in this situation the nerve- 
fibres are non-medullated, and hence transparent. 

The optic nerve spreads out into the retina r, and therefore in its 
middle there results a funnel-shaped depression — the vessel infundi- 
bulum — on the inner wall of which the central artery a, and the central 
vein v, rise upward. The choroid (ch) shows the cross-section of its 
numerous vessels, and towards the retina a dark border — the pigment 
epithelium. Next to the border of the optic nerve entrance the cho- 
roid is more darkly pigmented and corresponds to the choroid ring. 
At co a short posterior ciliary is shown passing through the sclera to 
the choroid. Between the border of the choroid d, and the border of 
the nerve-head c, a small interspace remains, in which the sclera is 
evident, and corresponds to the scleral ring visible in ophthalmoscopic 
examination. 

Physiological Variations. — The papilla, instead of being 
round, or slightly oval with a vertical long axis, is often dis- 
tinctly irregular in outline, or has its long axis in the hori- 
zontal direction. 

The physiological cup varies in shape, area, and depth. Nor- 
mally situated on the temporal side, it may be a deep pit, fun- 
nel-shaped, with overhanging margins over which the vessels 
sharply bend, or very shallow and dish-like, sloping to the tem- 
poral side, or deep and sharply marked on its inner side, but 
shading outward. 

The usual distribution of the vessels is subject to numerous 
variations, so much so that it would be difficult to find it the 
same in any two eyes. The usual departure from the ordi- 
nary type is the one already referred to, in which four major 
branches (two arteries and two veins) appear at the centre of the 
porus, instead of two large branches which later divide at or 
near the margin of the disc. Anomalies of the veins upon the 
disc, in the form of unusual bifurcations, are occasionally seen. 
Divisions of the vein just before entering the disc; division at 



OPHTHALMOSCOPY. 113 

the margin ; the formation of a vascular circle and final reunion 
in a single vessel : and anastomosis of the central vein with an 
aberrant vein, or one which has penetrated the inner side of the 
disc, have been described (Randall). The veins are normally 
m«>re tortuous than the arteries. Both sets of vessels present 
this appearance in marked degree as symptoms in certain patho- 
logical conditions, hut also occasionally as an anomaly without 
such significance (Xettleship). Again, the vessels may stand 
forward from the disc in a high curve, or twine around each 
other, as we sometimes see two stems on a vine. 

An anomaly of not infrequent occurrence is the presence of a 
cilio-retinal vessel; that is, one which passes into the margin of 
the disc at or near to it, then arches outward or away from the 
disc hefore it finally disappears in its passage toward the macula, 
to which it is usually destined. In a series of examinations, 
Lang and Barrett found this vessel present in 16.7, Veasey in 
14.2, and the author in 10.6 per cent. 

In addition to the variations just described, numerous anomalies 
are found, to which reference will be made in the sections devoted 
t< i the descriptions of the diseases of the retina and optic nerve. 

The Retina. — Inasmuch as the retina is practically transparent, 
a study of this membrane is hardly possible without a considera- 
tion of the underlying choroid and even the sclera. 

In certain persons, especially of dark complexion, the retina 
a— umes a grayish tint in the neighborhood of the papilla, most 
marked upon its nasal half. This faint opacity is slightly 
streaked, the striatums indirectly corresponding to the expansion 
of the optic nerve fibres. Eyes long subjected to the strain of 
uncorrected ametropia furnish an exaggerated picture of this 
appearance, which, if at all extensive and associated with similar 
opacities along the lines of the vessels, assumes pathological 
importance (see Retinitis). 

In the eyeground of young subjects, particularly along the 
line of the vessels, numerous wave-like glistening reflexes may 
be seen to follow one after another with the slightest movements 
of the ophthalmoscopic mirror. The effect is similar to the 
shimmer seen on the surface of certain silks, and has been 
designated by English writers " shot-silk retina." It is unusual 

8 



114 DISEASES OF THE EYE. 

to find the phenomenon in individuals over thirty, its occurrence 
being marked in direct proportion to the youth of the subject. 

Macula Lutea. — About two discs' diameter to the outer side 
of the papilla and slightly below the horizontal meridian, there 
is a circular, or slightly oval, spot, equal in area to the end 
of the optic nerve, darker in color than the surrounding fundus, 
uncrossed by any visible retinal vessel, but toward which the 
finer twigs of the major branches radiate, fringing its boundary. 
This region is the macula lutea, or yellow spot, and is that por- 
tion of the eyeground concerned with the functions of direct 
vision. 

Its centre is occupied by the foveal reflex, which marks the 
edge of the fovea centralis, and which may appear as a spot of 
light, a small circle with reddish centre, a shifting crescent, or a 
shining line. This, in turn, is surrounded by a dark area (the 
dark spot of the macula), sometimes containing a number of 
brownish-black or light-colored granules. Finally, the margin 
of the macula is bounded by a glistening whitish ring or halo 
(macular reflex). 

The method of examination determines whether all these 
characteristics of the macula lutea can be observed. They are 
fairly constant, however, with the exception of the halo, and are 
notable in young children. Ordinarily the macular ring is best 
seen with the indirect image in young eyes, when it is apt to 
assume an oval shape ; but according to Lindsay Johnson, even 
with the upright image, if the source of illumination be grad- 
ually lowered, a time is arrived at when more light is reflected 
from the macula than from the general fundus, and at that mo- 
ment the ring appears. In elderly people the region usually 
cannot be well recognized except by the absence of vessels and 
its darker color, but even in them careful focusing will not in- 
frequently reveal the foveal reflex. In albinos it is still more 
difficult to define this area. 

Although no vessels visible to the ophthalmoscope cross the 
macula, except as an anomaly (Randall, Johnson), the region is 
abundantly supplied with capillaries, as Mr. Nettleship has shown 
by artificial injection, which surround the fovea in a close limp, 
but do not occupy it. The student may find the region difficult 



OPHTHALMOSCOPY. 115 

to study because the light falling upon it causes the pupil to con- 
tract, the view being further hindered by the corneal reflex. 
Hence the pupil should he dilated, when the macula may be 
brought into view by requiring the patient to look directly into 
the ophthalmoscopic mirror, or may be found by turning the light 
outward from the lower edge of the disc. The region should 
always be studied with the utmost care. 

The appearances in the macula depend partly upon the dis- 
position of the layers of the retina in this region. At its margin 
the retina is much increased in thickness by an extra develop- 
ment of the layer of the ganglion cells, while the fovea is pro- 
duced by the hollowing out of the centre of the macular region. 
The macular reflex, or ring, therefore, may be considered as a 
reflection arising from the thickened macular circumference, and 
the foveal reflex as a reflection from the edge of the fovea. The 
variations, according to Johnson, are due to the direction and 
the shape of the sloping sides of the pit, but according to Dim- 
mer, depend upon the kind of ophthalmoscopic mirror which 
i- employed, the reflex being the inverted image of the centre 
of the mirror. According to Piersol, the color of the macula 
depends upon the presence of a yellowish pigment within the 
layers internal to the visual cells, the latter elements remaining 
colorless ; iu consequence of this arrangement, the fovea, in 
which the neuro-epithelium alone exists, is devoid of pigment, 
and, therefore, appears as a light spot within the colored area. 
The dark brown spot of the macula is generally believed to 
depend upon the thinning of the retina at this spot, with a 
more decided pigmentation in the epithelium. Dimmer, how- 
ever, thinks that it is also produced by absence of the slight 
veiling of the retina at this point, which is manifest in the sur- 
rounding more compact layers. 1 

The Choroid. — The bright glare which illuminates the pupil 

when the light is thrown into it from the ophthalmoscopic mirror, 

and develops into the uniform red color of the fundus, when this 

1 Those interested in this subject should consult Die OjMhalmosJcopischen Licht- 
reflexe der Netzhaut, by Dr. Friedrich Dimmer, Wien, 1891 ; an excellent article 
by Dr. G. Lindsay Johnson, entitled "Observations on the Macula Lutea," 
Archit,* of Ophthalmology, Vol, XXI. : and "The Eegion of the Macula Lutea iu 
Ophthalmoscopy," by Dr. M F. Weyuian, Ophthalmic Record, Vol. II., page 219. 



116 DISEASES OF THE EYE. 

is brought into view, arises from the choroid. The rays of light 
pass through the transparent retina to its pigment epithelium, 
which in ophthalmoscopic work is accredited to the choroid (see 
Fig. 51 B, ch), and in part are absorbed and in part reflected. 
The greater the quantity of the pigment, the greater the amount 
of absorption, so that the color of the eye-ground depends upon the 
degree of saturation in this epithelium, and varies from an almost 
slaty color in the dark-skinned races to a fiery red in persons of 
blonde complexion. 

In very fair people, the imperfect development of pigment- 
cells of the choroid exposes the larger choroidal vessels, which are 
evident as a mesh-work of tortuous red bands with intervening 
spaces of lighter or darker color, and which are distinguishable from 
the retinal arteries and veins by their flat appearance and absence 
of the light streak. The most perfect exposure of the choroidal 
vessels is seen in albinos. It is not usually possible with the 
ophthalmoscope to differentiate the arteries and veins of this 
system, although the latter are of greater size, and, near the 
equator of the eye, converge toward the vena? vorticosae, being 
separated by larger and longer spaces. In decided brunettes, 
these spaces are more deeply tinted than the vessels which appear 
" like light streams separated by dark islands" (Nettleship). A 
fair general idea of what tint may be expected in the fundus may 
be obtained by observing the color of the patient's hair. 

All of the details of the eye-ground may be studied with greater 
ease through a dilated pupil, and on beginning his studies the 
student may with propriety employ a mydriatic, cocaine, or 
homatropine, not atropine, provided no signs of glaucoma are 
present. Having acquired knowledge of the normal appearance 
thus seen, he must now practise with the undilated pupil. 

The disc and macula having been studied, the peripheral parts 
of the eye-ground should be examined by throwing the light 
inward, upward, and downward, the head of the observer being 
moved correspondingly to comply witli the changed direction of 
the mirror. Even when the central part of the fundus presents 
the usual characteristic red tint, the choroidal vessels are frequently 
exposed in the periphery presenting the appearance just described, 
and having no pathological significance. 



OPHTHALMOSCOPY. 1 1 7 

Determination of Refraction by the Ophthalmoscope. — The 
estimation of the refraction of the eye by means of the ophthal- 
moscope results in either a qualitative or quantitative determina- 
tion. 

The former is obtained in the following manner : Hold the 
ophthalmoscope 30 to 50 em. from the patient's eye, and looking 
through the central aperture of the mirror, unaided by a glass, 
observe if any vessels come into view. Their appearance means 
that the eye is either hypermetropic or myopic. Now move the 
head from side to side, and note if the vessels move apparently 
in the same or in a direction opposite to the movements of the 
head. If the former, the eye is hypermetropic ; if the latter, 
myopic. Inasmuch as the image of the vessels in low degrees 
of myopia would be formed only at a considerable distance from 
the observed eye (30 to 120 cm.), and since no sharp image would 
be obtained in either emmetropia or low degrees of hyperme- 
tropia farther away than 30 cm., any considerable degree of ame- 
tropia maybe excluded by failure to obtain a direct image except 
at a long range or a very short distance from the patient's eye. 

Before attempting a quantitative estimation of the refraction by 
means of the ophthalmoscope, certain fundamental rules must be 
observed : — 

1. Both surgeon and patient must hare relaxed accommodation. 
The ability to relax the accommodation comes with practice, and 
is best secured for the patient by requiring him to gaze inatten- 
tively into the farthest corner of the well-darkened room. 1 

2. A certain definite spot in the eye-ground upon which to focus 
should be selected. 

Naturally the macula, or region of accurate sight, would seem 
to offer the most desirable point ; but, owing to the difficulty of 
making accurate observation through the undilated pupil, which 
contracts when the light falls upon this region, and the dazzling 
corneal reflex, it does not serve a satisfactory purpose ; hence, it 
i- better to select the edge of the optic disc, or the medium-sized 
vessels midway between the disc and the macula, where two 
branches, running at right angles to each other, may readily he 
found. 



118 DISEASES OF THE EYE. 

3. The observer should approach as close as possible to the eye 
inula- observation. 

If he is able to place with the ophthalmoscope a correcting 
lens at a point 13 millimeters in front of the cornea, he has 
reached the anterior focal point of the eye, and the power of 
such lens would express the degree of ametropia, and be equiva- 
lent to one set in a frame which had been found by the usual 
tests to neutralize the refraction error. If he is unable to 
reach this point, and holds the ophthalmoscope with the cor- 
recting lens at a point farther away from the cornea than 13 
millimeters, the distance between the glass and the cornea 
must be subtracted from the focal distance of the correcting lens, 
in order to ascertain the real amount of hypermetropia, and be 
added to the focal distance, to obtain the degree of myopia. 

If the observer employs lenses ground according to the old 
system of notation, in which the number of the glass expresses 
its focal length, the following rule, taken from Loring, serves 
to determine the condition of refraction : " The ametropia in a 
given case is equal to the glass used plus the distance between 
it and the nodal point if the eye examined be myopic, minus 
the distance, if it be hypermetropic." 

4. /// order to ascertain correctly the refraction error, the ob- 
server must be emmetropic, or if not, render his eye emmetropic by 
using the proper correctmg lens, either in the form of spectacles or an 
equivalent glass placed behind the sight-hole of the ophthalmoscope. 

The emmetropic observer can see the details of the myopic 
eye-ground only dimly without the aid of a correcting glass, and 
not at all if the myopia is of high degree. By placing concave 
glasses behind the sight-hole of the ophthalmoscope, the con- 
vergent rays which leave the observed eye arc rendered less 
and less convergent until that glass is reached which just yields 
a distinct image, i. e., one which has rendered the convergent 
rays parallel. 

The emmetropic observer can see the details of a hypermetropic 
eye-ground distinctly without the aid of a correcting glass, unless 
the hypermetropia is of very high degree, by an effort of accom- 
modation which render- his crystalline lens more convex, and thus 
causes the divergent rays which leave a hypermetropic eye to 



OIMI'IIIAI.M' IS< I >PY. 



119 



become parallel. But, with accommodation relaxed, he sees dis- 
tinctly the details of the fundus through a convex lens placed 
behind the ophthalmoscope; this should he substituted for 

other stronger convex lenses until the strongest one is reached 
wiili which a clear image is still possible, i. e., one which has 
rendered the divergent rays parallel, while the next highest 
number creates a blur over the details of the eye-ground. 

From what has been said it follows: The strongest convex 
lens, placed in position in the ophthalmoscope, with which the 
emmetropic observer can still sec the details of the fundus at the 
point selected, measures the degree of hypermetropia ; the weakest 
concave lens, the degree of myopia. The hypermetropia usually 
is somewhat greater, and the myopia somewhat less, than the 
result obtained by ophthalmoscopic examination. 

In order to estimate the refraction of the eye examined, the 
hypermetropic observer must subtract from the convex, or add 
to the concave lens, which yields him a sharp image of the fundus, 
the amount of his own error, while the myopic observer must 
add to the convex, or subtract from the concave lens, with which 
he sees by the eye-ground the degree of his own near-sightedness. 

In order to calculate the amount of lenothenina; or shortening; 
of the eye equal to a lens which neutralizes the myopia or hyper- 
metropia in any given case, and provided the distance between 
the surgeon's eye and that of the patient is not more than 2.5 cm.. 
the following table, which is taken from Nettleship, and which 
he has altered from Knapp, is useful : — 

H. of ID represents a shortening of 

11 2 " '• " 

" 3 



6 

9 

12 

18 



M. of 1 D represents a lengthening of 



>; 

9 
12 
IS 



v.o 
. 0.5 


11111 
U 


. 1 


I i 


. 1.5 


" 


. 2 


(I 


. 3 


(( 


. 4 


(( 


. 6 


11 


. 0.3 mm 


. 0.5 


1 1 


. 0.9 


It 


. 1.3 


" 


. 1.75 


11 


. 2.6 


(t 


. 3.5 


II 


. 5 


(1 



120 DISEASES OF THE EYE. 

By this table the depth of an excavation in the papilla may 
be measured. For instance, it' the bottom of the pit required 
— 5 1) tor its sharp examination, and the margin of the nerve 
was seen without any glass, the depth of the excavation would 
be 1.3 mm. 

The presence of astigmatism may be ascertained by means of 
the ophthalmoscope and the upright image, and, in skilled hands, 
its amount measured with reasonable accuracy. 

In all such examinations the instrument must be close to the 
eye and in an exact perpendicular line, and the following points 
observed : — 

(a) The optio disc is an ellipse, its long axis corresponding with 
the meridian of the greatest refraction, and its short axis with 
the meridian of least refraction. When the principal meridians 
are vertical and horizontal, the disc usually is a vertical oval, 
more rarely a horizontal oval. 

When the principal meridians are inclined, they sometimes 
correspond to the direction of the long and short axes of the 
ellipse assumed by the nerve-head. As, however, the disc is 
often oval in non-astigmatic eyes, this evidence is not satisfactory. 

(b) All points of the portion of the fundus under examination 
are not in focus at the same time, e. g., the retinal vessels running 
in the directions which correspond to the principal meridians. 

Thus, when two vessels cross each other at right angles, the 
vertical branch may be sharply seen, while the horizontal one 
presents a blurred image, or the upper and lower margins of the 
disc may be clear, but the lateral borders indistinct. The amount 
of hypermetropia, or of myopia, of the vertical meridian is equal 
to the strongest convex, or weakest concave, glass which makes 
distinct the vessels running in a horizontal direction. The retrac- 
tion of the horizontal meridian is determined by the glass which 
yields a clear image of the vessels running in a vertical direction. 
As the vessels do not correspond to the layer of the rods and 
cones, the measurement is an approximation. 

If a vertical vessel is sharply seen with a convex lens of 3 D, 
while the vessels at right angles to it are clearly visible without 
the aid of anv glass, and blurred by the addition of a convex 
one, hypermetropia of 3 D exists in the horizontal meridian, 



OPHTHALMOSCOPY. 121 

because a line, in this case a vessel, appears most distinct in 
the meridian of greatest ametropia, inasmuch as it is seen by 
means of the rays passing through that meridian of the cornea 
which lies at right angles to its course (see page 168). If, in 
another eye, the vertical vessels appear distinct without the aid 
of a glass, and the horizontal vessels require a concave lens of 
3 1 > to bring them into focus, myopia of 3 D exists in the vertical 
meridian. In the one instance, there is simple hypermetropic 
astigmatism which would require a + 3 D cyl., axis vertical, for 
it- neutralization; and in the other, a simple myopic astigmatism 
demanding a — 3D cyl., axis horizontal, for its correction. 

Compound astigmatism is determined by finding, in hyper- 
metropia, the strongest convex lens which the vessels in each 
meridian will bear with the preservation of a distinct image, and 
subtracting the one from the other, thus finding the difference 
between the meridians, i. e., the amount of astigmatism. Thus, 
if the vertical vessels remain in focus when viewed through a 
+ 3D lens, and the horizontal vessels through a + 1 D, there 
is a general hypermetropia of 1 D, with a difference of 2 D, 
between the principal meridians. This difference of 2 D repre- 
sents the amount of the astigmatism. In the same way, myopia 
of varying amounts in each meridian is measured. The correct- 
ing glass in the first instance would be + 1 D sph. 3 + ^ D cyl., 
axis vertical. 

If the vertical vessels are distinctly seen with +3D, while 
the horizontal vessels require a — ID for their perfect detection, 
myopia of 1 D exists in the vertical meridian, and hyperme- 
tropia of 3 D in the horizontal meridian. There is an astigma- 
tism in this case of 4 D. The principal meridians are respectively 
myopic and hypermetropic, constituting what is termed mixed 
astigmatism. (Compare page 166.) 

The measurement of astigmatism in this manner, with any 
degree of accuracy, requires a vast amount of practice, a perfect 
control of the accommodation, and even then must never be em- 
ployed to the exclusion of other and more trustworthy methods. 

(2) The Indirect Method (method of the inverted image). 

The patient and surgeon are seated in the same relative posi- 
tions as have alreadv been described in connection with the direct 



122 



DISEASES OF THE EYE. 



method, and, if the right eve is to be examined, the ophthalmo- 
scope is held in the right hand at a distance of 30 cm. from the 
patient, who is instructed to look at the right ear of the examiner. 
A convex lens of 20 D, held between the surgeon's left thumb 
and index finger, while the remaining fingers are rested upon the 
brow to steady the hand, is placed at about its own focal length 
in front of the patient's eye, directly in the path of the rays re- 
turning from the fundus, which are thus brought to a focus and 
form an aerial image between the observer and the glass. 

If the left eye is to be examined, the ophthalmoscope is held 
in the left hand, and the patient instructed to look at the surgeon's 
left ear, while the lens, grasped in the fingers of the right hand 
in the manner just described, is placed in position. 



Fig. 52. 




Method of the indirect examination with the ophthalmoscope. 

Much practice is required to gain perfect control of the illumi- 
nation, and at the same time to keep the ophthalmoscope, lens, 
and patient's eye in proper relation. This is largely due to the 
difficulty of securing perfect accord between the relative positions 
of the two hands. While the beginner endeavors with one hand 



OPHTHALMOSCOPY. 123 

to place the lens properly before the patient's eye, hia attention 
for the moment is distracted from the other hand which holds 
the ophthalmoscope, and this becomes unsteady and permits the 

light to shift from the pupillary ana. 

This difficulty having been overcome, facility in using the 
supplementary lens, or, as it is often railed, the object-glass, 
must be acquired, especially to avoid the confusing reflexes from 
it- surfaces, and the magnified image of the iris. This is besl 
accomplished by holding it in a slightly oblique direction, and 
at a point a little farther away from the cornea than its own 
focal Length. The glass should now be moved up and down, 
back and forth, to obtain alterations in focus and displacements 
of the image from side to side, and a parallax between points 
situated at different levels in the eye-ground. 

The image which is found at a certain distance in front of the 
object-glass may not present itself to the observer as a distinct 
picture, owing to his inability to accommodate for the point of its 
formation. This accommodative strain may be relieved, and the 
image magnified, by placing behind the ophthalmoscope a convex 
glass of 5 D which adapts the emmetropic observer, with relaxed 
accommodation, for a point 20 centimetres distant. If the ob- 
server is presbyopic, or has a deficient amplitude of accommoda- 
tion, this additional lens is absolutely necessary; while, if he is 
hypermetropic, the degree of his hypermetropia should be added 
to the glass used as a magnifier. The observer possessing a 
moderate degree of myopia requires no lens in the ophthalmo- 
scope, because he views the aerial image at his far point, while, if 
his myopia is of high grade, he will need a weak concave glass. 

If, then, the examiner, having illuminated the pupil from a 
distance of 00-50 cm., finds the slightly yellowish area in the 
general red glare indicating the position of the optic papilla, and 
places the convex lens (object-glass) in position, and the second 
convex lens (eye-piece) behind the ophthalmoscope and secures 
an aerial image, he will observe the following characteristics in 
contrast with the appearances seen by the direct method; always 
remembering that the picture is inverted, and that what appa- 
rently is on the nasal or inner side really belongs to the outer or 
temporal side ; that what apparently is below really is above : — 



124 DISEASES OF THE EYE. 

1. The field is larger. 

Not merely the object, the optic nerve for example, comes into 
view, but also a portion of the surrounding eye-ground, precisely 
as a more extensive portion of the field of the microscope is 
obtained through an objective of low power than through one of 
high power. 

2. The individual objects in the field are smaller and more 
sharply defined, but the finer detail* are less perfectly revealed, 
because seen under a loiter magnifying power. 

The relation between the extent of the fundus visible and the 
size of the details depends upon the strength of the supplementary 
convex lens (object-glass). If this is strong, the expanse of the 
field brought into view will be greater, while the component 
parts will be smaller (Loring). Hence, if it is desired to enlarge 
the image of the fundus at the expense of its extent seen at one 
time, instead of a 20 D convex glass, one of 10 D should be 
employed. 

3. The differentiation between objects of similar appcareince, 
e. g. y the vessels, is less perfect. 

Working under these conditions the student will observe that 
the optic papilla is smaller, its edges more sharply defined, and 
the faint veiling of the nasal margins caused by the stria! ion of 
the surrounding retina less noticeable. 

The difference between veins and arteries is not so marked as 
with the direct method, and it may be well-nigh impossible to 
distinguish from each other the finer twigs of each system. As 
a rule the veins, being larger and darker, present a more distinct 
image than the arteries, which are slightly blurred in outline. 
The light streak, so noticeable in the upright image, is frequently 
wanting. 

The macular region, especially if the pupil is not dilated, pre- 
sents unusual difficulties in its study. If the patient is required 
to look directly into the opththalmoscope, this illumination of 
the macula causes a contraction of the pupil (if the iris is not 
under the influence of a mydriatic), and brings into existence 
confusing reflections. It is best brought into view by first finding 
the papilla, and then moving the object-glass horizontally across 
the line of vision until its inner margin corresponds with the 



OPHTHALMOSCOPY. 125 

outer border of the pupil. In young subjects a bright reflex 
encircles an elliptical dark area containing in its centre a reddish, 
or, less frequently, a bright point surrounded by a small brilliant 
ring. These characteristics are sometimes lacking- in adults, and 
may not be present in children. Under these circumstances, the 
macula is distinguishable only by the ill-defined appearances of 
a darker tint and an absence of vessels. (See page 114.) 

Estimation of Refraction by the Indirect Method. — A quali- 
tative estimation of the refraction may be ascertained with the 
mirror alone by observing if any portion of the fundus comes 
into view when this is held at a distance of 50 cm., and if this 
image, the observer's head being turned slightly from side to side, 
shifts apparently in the same or an opposite direction to the move- 
ments of the head. (p. 117.) 

The measurement of the degree or quantity of the refraction by the 
indirect method is possible by attending to the following directions 
adopted by Koenigstein : Since the rays which proceed from an 
emmetropic eye are parallel, the image of its fundus appears at 
the focus of the convex lens (object-glass), while that of the hy- 
permetropic eye is developed farther from, and that of the myopic 
eye nearer to, the lens. In order to ascertain the degree of ame- 
tropia this distance must be known and we proceed in the fol- 
lowing manner : — 

If the observer is not naturally myopic, he renders himself 
so by employing a convex lens behind the mirror, for example, 
5 D, which puts him in the condition of a myope with a far 
point of 20 cm., i. e., he cannot see distinctly beyond this point. 
If, now, the inverted image is developed through a lens of 
10 D, held at its focal distance from the cornea, and the dis- 
tance between the ophthalmoscope and the lens measured, the 
observer will also ascertain, if he does not accommodate, the dis- 
tance of the image from the lens, and from this calculate the re- 
fraction, as may be understood from the following example : The 
inverted image is developed, the observer withdraws to the 
farthest point from which he can still see the image distinctly, 
and measures the distance between the ophthalmoscope and the 
lens, which he finds is 30 cm. It follows, as- his far point lies 
at 20 cm. (he being artificially myopic in this degree), that the 



12G DISEASES OF THE EYE. 

image is 10 cm. from the lens, or at its focus ; the rays have pro- 
ceeded in a parallel direction from the observed eye, and this is 
emmetropic. If the distance between the ophthalmoscope and 
lens is greater, e. g., 35 cm., then the image is 35-20 = 15 cm. 
distant from the lens and the refraction is hypermetropic, in this 
instance, 5 D. If the distance is shorter than 30 cm., e. g., 25 
cm., then the image is situated between the lens and its focus, 
and the refraction is myopic, also 10 D. 

High grades of myopia may be calculated by a simple meas- 
urement of the distance. Rays proceed from a myopic eye 
convergent and form an inverted image at its far point, without 
the aid of an object-glass. The distance between the eye and 
the ophthalmoscope is taken, and from this is subtracted the far 
point of the observer. If, for example, an emmetrope with 
+ 4D observes the inverted image of the fundus distinctly, and 
the.measurement between the observer and the observed eye yields 
35 cm., the former having a far point of 25 cm., the image is 10 
cm. distant from the observed eye, and the myopia 10 D. 

For practical purposes, this method does not enjoy material 
advantages, and is open to the serious objection of inability to 
secure accurate measurements, especially in hypermetropia. Its 
field of usefulness is almost entirely limited to very high grades 
of myopia. 

Estimation of Astigmatism by the Inverted Image. — The 
existence of astigmatism is determined with the indirect method 
by the changes which take place in the shape of the optic nerve, 
as the refractive condition of the eye varies in its different parts. 
In the direction of least refraction, the image of the nerve con- 
tracts as the lens is withdrawn ; in the direction of greatest refrac- 
tion, the image of the nerve expands; in the absence of astigma- 
tism, the round or oval shape of the nerve is not altered whether 
the lens be held close to the eye, or removed from it. In direct 
ophthalmoscopy, the disc usually is a vertical oval when astigma- 
tism exists; the same disc viewed by the indirect method, with 
the lens held close to the eye, is a horizontal oval, but as the lens 
is withdrawn farther from the eye, it becomes a vertical oval. 
This may be produced in different ways. 

If the horizontal diameter is diminished bv withdrawing the 



OPHTHALMOSCOPY. 12] 

lens, the astigmatism is hypermetropic, but if the vertical diameter 
is increased by removing the lens, the astigmatism is myopic; if 
both diameters arc diminished, but one more than the other, the 
astigmatism is compound hypermetropic; if both diameters are 
increased, but oik- mure than the other, the astigmatism is com- 
pound myopic. The must marked effect is produced in mixed 
astigmatism, where the myopic vertical meridian causes the disc 
to spread out vertically, while the hypermetropic horizontal 
meridian causes it to dwindle in the transverse direction. The 
disc then shoots out rapidly in the vertical direction, while in 
the horizontal direction it rapidly contracts. 

Ophthalmometry. — This term indicates mensuration of the 
eye and as usually employed is limited in its application to the 
measurement of the radius of curvature of the cornea (heratom- 
> try i. In order to practice ophthalmometry, instruments for taking 
the measurement of the radius of curvature of the cornea have been 
devised, and are known a~ ophihcdmometei'S. The ophthalmometer 
most in use is the one devised by Javal and Schiotz. 

The following description, modified from the one given by 
Dr. Xoyes, gives the essential points of the instrument : There 
are two objects ; the one fixed in position, bearing a white recti- 
linear figure; and the other one, sliding back and forth on the arc, 
i- composed of white enameled blocks, each one of which is calcu- 
lated to represent one dioptre of corneal refraction, or a power 
equal to a cylinder of one dioptre. The movable object and the 
stationary white rectilinear figure are placed so that their images 
will be reflected from the cornea. These reflections, which are 
viewed by a small telescope, are doubled by passing through a 
prism placed between two biconvex lenses, and having in addition 
a third biconvex lens which shortens the posterior foci of the two 
images, which foci are marked by a thread of spider's web. The 
patient's face is placed in the frame and is steadied by a chin and 
forehead rest. The telescope stands upon a tripod which can be 
moved forward and backward in order to obtain the proper focus. 
The central images are obtained sharply on the spider web, and 
the movable object passed along the arc of the instrument until 
it comes in contact with the rectilinear figure. This having been 
done, its position on the arc is read off upon an index. The 



128 DISEASES OF THE EYE. 

arc is then turned at right angles to this position, and the relation 
of the two images noted. If they have not changed either by 
overlapping or separating, the curve of the cornea is the same 
both horizontally and vertically. If the images overlap in the 
vertical meridian, the radius of the curve is shorter in this meri- 
dian, and there is astigmatism. If the images separate with the 
bar vertical, this meridian has a longer radius than the horizontal, 
and again there is astigmatism. Each enameled block, as before 
stated, has been calculated to express one dioptre of corneal re- 
fraction, and consequently the amount of astigmatism is read off. 

This is the best objective test of corneal astigmatism which we 
possess, and is of the greatest service in determining the refraction 
of the cornea and the direction of its principal meridians. It 
should not be used to the exclusion of other methods or the 
employment of mydriatics. 

Optometry is a term which indicates the principles involved 
in the measurement of the refraction of an eye by its limits of 
distinct vision. The instrument which thus serves to determine 
the refraction of the eye is called an optometer. 

Optometers are based upon a number of principles. For in- 
stance, a single Convex lens by which the direction of the luminous 
rays emanating from an object is changed, and consequently the 
determination of the refraction of the eye rendered possible, con- 
stitutes an optometer. Other optometers are based upon the 
principle of a telescope; still others upon the measurement ot 
circles of diffusion ; upon Scheiner's experiment, and upon the 
chromatic aberration of the eye. It would not be possible, in the 
limits of this manual, to describe in detail the principles involved 
or the various forms of apparatus which have been employed. 
Should the student desire to pursue the subject, he may with ad- 
vantage consult the chapter devoted to this method found in 
Landolt's Refraction and Accommodation of the Eye. 

Retinoscopy 1 [Skiascopy, or the Shadow Test]. — This is a 
method of determining the refraction of the eve bv observing; the 
direction in which the light appears to move across the pupil, 
when the mirror by which light is thrown upon the eye in the 
dark room is rotated. 

1 The section on Retinoscopy has been prepared by Dr. Edward Jackson. 



RETINOSCOPY. 129 

With the ophthalmoscope, as has already been explained, one 
may look into a myopic eye from close in front of it, and see an 
erect image of the fundus, which he can render clear by the proper 
concave lens; or, from a greater distance, he can view an inverted 
image of the fundus, with or without the intervention of a con- 
vex lens. The point at which the change from the erect to the 
inverted image occurs has been called the point of reversal. It 
is the point for which the eye is focused, and is the far point of 
distinct vision. Retinoscopy is simply an accurate method of 
determining this point of reversal. 

To apply the test the surgeon faces the patient at a distance of 
about one metre, and, holding the mirror to his own eye, reflects 
on the patient's face the light from a lamp, placed near the sur- 
geon, and covered with an opaque shade having an aperture 
1 centimetre in diameter, if the plane mirror is employed, or 
placed behind the patient, if the concave mirror is used. By 
rotating the mirror the area of light it throws on the face is made 
to move up and down, or from side to side, or obliquely. The 
part of the light that falls on the patient's pupil is condensed on 
his retina, forming there a small light area which also moves about 
as the mirror is rotated ; for the plane mirror it always moves 
with the light on the face, and for the concave mirror in the 
opposite direction. 

Fig. 53. 




Retinoscopy with the plane mirror. 

In Fig. 53 L represents the lamp-flame, screened from the 
patient, and A and B two positions of the plane mirror. When 
the mirror is at A, the light that enters the eye will come as though 
from a flame at /, and will be condensed toward a, on the lower 
part of the retina. At this time the light falls on the lower part 
9 



130 DISEASES OF THE EYE. 

of the face. But when the mirror is rotated to B, the light 
entering the eye conies from the direction I', and is condensed 
toward b, on the upper part of the retina. At the same time 
the light on the face moves upward. The positions of the retina in 
hypermetropia, emmetropia, and myopia are shown at H, E, and 
31. It will be noted that in all these forms of ametropia, the 
movement of the light on the retina is with the light on the face. 
In Fig. 54 the action of the concave mirror is represented. 
When the mirror is at A, the light that enters the eye comes 

Fig. 54. 




Retinoscopy with the concave mirror. 

from the focus of the mirror at I, conjugate to the position of the 
lamp-flame, and is condensed toward a, on the upper part of the 
retina ; and when the mirror is at B the light enters from V } the 
new position of this conjugate focus, to be condensed toward 6, 
on the lower part of the retina ; that is, as the light has moved 
upward on the face, it has moved downward on the retina, and 
this is true for either H, E, or M. 

The following account assumes the use of the plane mirror ; 
but will apply equally to the concave mirror, if one bears in 
mind that with the latter the movement in the pupil is always 
in the opposite direction, and changes lenses instead of distance 
(page 135). 

We have thus seen what is the real movement of the light on 
the retina, as it would always appear in the back of an enucle- 
ated eye with the sclera and choroid removed, but the surgeon 
does not see it in that way ; he can only watch the apparent 



RETINOSCOPY. 131 

movement as seen through the pupil. This will be the same as 
the real movement, with the light on the faee [plane mirror] 
when he sees an erect image, and in the opposite direction when 
he sees an inverted image. 

In Fig. 55, M represents a myopic eyeball, from the retina of 
which rays come out and are focused at B, the point of re- 

Fig. 55. 




Rays coming from a myopic eyeball. 

versa!. Anywhere closer to the eye than this, as at A, an erect 
image is seen ; the light in the pupil seems to move with the 
light on the face. Anywhere beyond the point of reversal, as at 
C, an inverted image will be seen, and the light in the pupil will 
appear to move against the light on the face (see page 149). Just 
at the point of reversal B, it is impossible to see which way the 
light moves, and the illumination of the pupil is very feeble. 

At one or two dioptres from the point of reversal the light is 
comparatively bright. As the examiner goes farther than this 
from the point of reversal, it becomes more and more feeble. 
AVith the same movement of the mirror the apparent movement 
of the light in the pupil is quicker as the point of reversal is 
approached. These variations in the degree of illumination and 
rapidity of movement aid the expert retinoscopist to a diagnosis, 
but the thing mainly depended on is the direction of the move- 
ment. 

Application in Myopia. — If the surgeon, on throwing the 
light into the eye, finds that its apparent movement in the pupil 
is against the light on the face, he must be farther from the eye 
than the point of reversal (i>, Fig. 55) ; so he approaches the 
patient, still rotating the mirror and watching the apparent 
movement of the light, until he finds this is with the light on 



132 DISEASES OF THE EYE. 

the face (A). He is now closer to the patient than the point of 
reversal, and should draw back and observe the greatest distance 
(A) at which this movement with the light on the face can be 
distinguished ; then, drawing farther back, he observes the nearest 
point to the eye (C) at which the inverted movement can be seen, 
and the point B, half way between A and C, is to be taken as 
the point of reversal. These observations should be repeated until 
the exact position of B is established. The distance from B 
to the eye is then measured ; it is the focal distance of the glass 
required to correct the myopia. For instance, if the erect move- 
ment is seen as far as 55 cm. from the eye, and the reversed 
movement as near as 80 cm., the point of reversal will be about 
67 cm., and the myopia, therefore, 1.50 D. 

If the myopia thus discovered is high, its amount can be most 
accurately determined by putting on a concave lens that will 
correct all of it but 1 or 2 D, measuring what is left by retinos- 
copy, and adding this to the strength of the lens used for the 
total myopia. 

If, on the other hand, the myopia is very low, the point of re- 
versal may be at so great a distance that when near it one cannot 
see which way the light is moving in the pupil. In this case a 
weak convex lens must be placed before the eye, the point of 
reversal found with the lens, and then the strength of the lens 
deducted from the myopia this indicates. 

Application in Hypermetropia. — Here the rays from the 
retina emerge divergent, as shown by the broken lines in Fig. 56, 
and there can be no point of reversal. The surgeon finds the ap- 
parent movement of the light in the pupil is with the light on the 
face, and it continues to be so, no matter how far he draws back. 
It is necessary, then, to place a convex lens L before the eye, 
strong enough to render the rays convergent, and so to make a 
point of reversal. This lens does two things : First, it over- 
comes the divergence of the rays ; this takes part of its power. 
Second, the remainder of its power makes the rays converge, 
causing a sort of artificial myopia. The point of reversal (B) 
obtained is the point for this artificial myopia. It is to be de- 
termined as for natural myopia, and the amount of myopia it 
represents deducted from the total strength of the lens. The 



RETINOSCOPY. 133 

remainder will be the power required to overcome the divergence 
of the rays, and the strength of lens needed to correct the hyper- 
met ropia. 

Fig. 56. 




Rays emerging from a hypermetropic eye. 

For example, suppose the movement of the light in the 
pupil is found at all distances to be with the movement of 
the light on the face, and on placing a 5 D convex lens before 
the eye, it is found to be still with the movement of the light on 
the face when the examiner approaches to a little within one 
metre, but appears reversed if looked at from a distance slightly 
greater than one metre. The point of reversal then is at one 
metre ; 1 D of the strength of the lens is making the rays con- 
vergent, while the other 4 D have been used to overcome the 
divergence of the rays as they came from the eye. Therefore, 
the eye must be 4 D hypermetropic. For accuracy, it is better 
here, as in the case of natural myopia, to make the final deter- 
mination with a lens that brings the point of reversal 1 or 2 
metres from the eye. 

Application in Emmetropia. — The application of retino- 
scopy is precisely the same as in hypermetropia ; but it is found 
that the artificial myopia caused by the convex lens equals the 
full strength of the lens, proving that the rays must have emerged 
from the eye parallel. 

Application in Regular Astigmatism. — The principles 
involved and the methods to be employed are essentially the 
same as in myopia or hypermetropia ; but the refraction has to be 
determined in the principal meridians, instead of in any meridian 
indifferently, as it can be where all meridians are alike. To de- 
termine the refraction in a certain meridian the light must be 



134 DISEASES OF THE EYE. 

made to move back and forth in that particular meridian, by- 
rotating the mirror about an axis at right angles to it. 

The direction of either of these principal meridians is revealed 
by the area of light in the pupil assuming the form of a more or 
less distinct band of light, extending across the pupil in the 
direction of this meridian, when its point of reversal is ap- 
proached. For the higher degrees of astigmatism this band is 
very noticeable, and fixes with the greatest accuracy the direc- 
tion of the principal meridian. When the band-like appearance 
is most noticeable, it is easy to cause its apparent movement from 
side to side ; but it is more difficult to distinguish the movement 
in the direction of the length of the band. Still, this latter move- 
ment is the one that is to be especially watched, and its reversal- 
point determined. 

"When the amount of astigmatism is very low, the appearance 
of a band may be very indistinct, or not at all perceptible ; but 
in such cases it is found that when we have reached the point of 
reversal for movement of the light in one direction, there is still 
distinct movement, either direct or inverted, in the direction at 
right angles to this, and we thus know we have tested one meri- 
dian of an astigmatism, and must in the same way ascertain the 
point of reversal for the other at right angles to it. When the 
surgeon is closer to the eye than the point of reversal for either 
meridian, the movement will be with the light on the face in all 
directions. When he is at the point of reversal for the meridian 
which has its point nearer to the eye than the other meridian, there 
will be no distinguishable movement in this direction, but still a 
direct movement at right angles to it. When he is between the 
two points of reversal, there will, in the direction of the nearer 
meridian, be an inverted movement of the light, but in the other 
meridian a direct movement. When the farther point of re- 
versal is reached the direct movement in its meridian ceases, 
while the movement in the other meridian continues inverted. 
When the surgeon has drawn back beyond both points of re- 
versal the movement is reversed in all directions. 

Having determined the amount of myopia, natural or artifi- 
cial, in both principal meridians, the strength of the cylinder re- 
quired to correct the astigmatism will of course be the difference 



MYDRIATICS. 135 

between the refraction for the two meridians. Having thus 
ascertained it, it is well to put this cylinder before the eye and to 
see if it does accurately correct the astigmatism, giving the same 
point of reversal for all meridians of the cornea; and, for accu- 
racy, the spherical lens which will bring this point of reversal to 
the distance of 1 or 2 metres should be used with it. 

Application in Ibkegulab Astigmatism. — If the pupil is 
dilated, it will always be found that the refraction of the eye varies 
in different parts of it, so that points of reversal for different 
parts of the pupil lie at different distances in front of the eye; 
and at the point of reversal and near it, both direct and reversed 
movements of the light are visible at the same time in different 
parts of the pupil. Usually, there is at the centre of the pupil 
a considerable area that has about the same point of reversal, 
and this is the part to which attention should be paid, the re- 
fraction in the other parts of the pupil being of less practical 
importance. 

When this central area of the pupil differs materially in refrac- 
tion from the ring that surrounds it, the eye is said to present 
aberration, which is called positive when the centre of the pupil is 
more hypermetropic or less myopic, and negative when the opposite 
is the case. When the aberration is high, on examining it from 
near the point of reversal of the margin of the pupil, the move- 
ment of the light will be swift at the margin, and slow in the 
centre, making it look as if the light in the pupil were wheeling 
around a fixed point at the centre. This appearance is marked 
in conical cornea. Aberration of moderate degree causes the 
appearance of a ring of light at the margin of the pupil, which 
has a very distinct movement, when the point of reversal for the 
centre of the pupil has been reached. 

The Concave Mirror. — With the concave mirror the move- 
ment in the pupil is reversed (page 130); and one cannot vary- 
much the distance of the mirror from the patient's eye, but must 
keep a fixed distance (usually 1 metre), and bring the reversal to 
this point bv changing the lenses used before the eye. 

The Use of Mydriatics. — In addition to the local medicinal 
value of the mydriatics in the treatment of diseases of the eye, 
e. y., iritis, these drugs are employed as aids of an accurate 



136 DISEASES OF THE EYE. 

determination of ametropia. With the ophthalmometer, without 
the aid of mydriatics, and with the method of retinoscopy, in the 
absence of prolonged mydriasis, good results are obtained ; but 
it is a safe rule in all cases of suitable age, and in the absence of 
contra-indicating symptoms, to employ an active mydriatic before 
attempting to select correcting lenses. This remark applies par- 
ticularly to cases of astigmatism. The mydriatic accomplishes 
three purposes : — 

(a) It dilates the pupil, and permits a thorough exploration of 
the interior of the eye, as well as a more perfect examination of 
the lens and vitreous humor than could be obtained without its 
aid. The student should not, of course, think it necessary to 
dilate the pupil of each eye which he subjects to an ophthalmoscopic 
examination ; but glasses should never be adjusted without a 
thorough knowledge on the part of the examiner of all the de- 
tails of the eye-ground and the transparent media. 

(6) It paralyzes the action of the ciliary muscle and places 
the accommodation in abeyance, rendering manifest types of 
ametropia which otherwise would remain latent. 

(c) It fulfils the important function of giving, during the time 
of its action, physiological rest to the eye that is under its influence, 
and consequently helps to subdue any retino-choroidal disturb- 
ance or other congestive condition that pre-existing eye-strain 
may have originated. No matter how perfect the correction of 
an optical error may be, if the coats of the eye are not in a 
healthy condition, or have not received a tendency to reach such 
a state, the correcting lenses will not be comfortable. 

In practice, various mydriatic drugs are employed, the most 
common being the sulphates of atropine, hyoscyamine, hyoscine, 
and duboisine, and the hydrobromate of homatropine and 
scopolamine. 

(1) Atropine. — Atropine is usually employed in a strength of 
four grains to the ounce. A drop of such a solution dilates 
the pupil in about fifteen minutes, and a very few moments later 
begins to paralyze the accommodation, which sustains a full 
paralysis in about two hours. The effect of atropine upon the 
accommodation remains for a week, but if, as is commonly the 
case, the drug is used for several days at a time, this influence is 



MYDRIATICS. 1 37 

much prolonged, and full return to the previous power of accom- 
modation is not secured for about twelve or fourteen days. 

In using atropine drops for the purpose of correcting errors 
of refraction, a solution of the strength given above should be 
dropped into the eye, one drop at a time, three times for at 
least a day, preparatory to the determination, and in young 
subjects possessing hypermetropic eyes, with active ciliary mus- 
cles, especially if there is associated spasm of accommodation, 
the drug must be continued for several days, or even longer, 
before the desired result is reached. 

(2) Hyoscyamine is usually employed in the strength of two 
grains to the ounce, in the same manner. It produces wide dila- 
tation of the pupil and complete ciliary paralysis, the effect of 
which is from six to seven days in duration. Many surgeons 
prefer this drug to atropine, and believe that its effects are equally 
good, while it enjoys the advantage of a much more temporary 
action upon the function of the ciliary muscle. The salt must 
be neutral, and the solution filtered through neutral paper (Risley). 

(3) Hyoscine and Duboisine in similar strength have similar 
actions, the latter drug being even more transitory than hyoscya- 
mine in its effect, return to accommodative power occurring in 
from four to five days. Both of them have the disadvantage 
of producing marked constitutional disturbances, at times ren- 
dering their employment disadvantageous. 

(4) Homatropine is a drug which produces a very transitory 
effect upon the ciliary muscle, full return of accommodation 
occurring in about fifty hours after the last instillation. 

To use this drug properly, it must be employed by cumulative 
instillations in the strength of eight to sixteen grains to the 
ounce, one drop of such solution being used every ten or fifteen 
minutes for an hour and a half preceding the determination, 
and then waiting forty minutes. At the end of this time the 
maximum effect of the drug upon the accommodation is secured. 
In the opinion of some surgeons, this drug is an insufficient 
paralyzer of accommodation, but if caution in regard to the 
cumulative instillations is observed, and the rule given above 
carefully followed, very satisfactory results may be obtained. 
Both its mydriatic and cycloplegic effects are increased by add- 



138 DISEASES OF THE EYE. 

ing to it a two per cent, solution of cocaine. Its influence may 
be neutralized by eserinc 1 

Scopolamine, introduced by Raehlmann, may be employed in 
one-tenth to one-fifth per cent, solutions, one drop every fifteen 
minutes for one and one-half hours, the duration of the effect 
being somewhat shorter than after the use of a one per cent, solu- 
tion of atropine ; according to some observers (Pooley, Martelli), 
its effects are much more transitory — three to five days. Myd- 
riasis begins in twelve, and is complete in thirty minutes; 
cycloplegia occurs in about forty-five minutes. Toxic symptoms 
— staggering, vertigo, and dryness of the throat — may develop. 
It is said to be more valuable than atropine in inflammatory 
affections of the eye, and not to increase intraocular tension 
(Raehlmann). 

It is not safe to use strong mydriatics in elderly people, and 
they must never be employed if there is any symptom of glau- 
coma. It is unnecessary to use them when that age has been 
reached after which the accommodation is so weakened that 
hypermetropia ceases to be latent. 

Hydrochlorate of cocaine, in addition to its anaesthetic action, 
is, in two to four per cent, solution, an excellent mydriatic, but its 
effect upon the accommodation is so slight that it is valueless for 
the purpose of preparing an eye for the estimation of any error 
of refraction. Groenouw has introduced ephedrine-homatropine 
(1 : 10). It is a rapidly acting mydriatic without effect upon 
accommodation. 

1 For further information in regard to the comparative value of the 
mydriatics the student should consult the valuable papers on the subject 
by Dr. S. D. Risley, in the Transactions of the American Ophthalmological 
Society. 



NORMAL AM» ABNORMAL REFRACTION. 139 



C II A PTER IV. 

NORMAL AND ABNORMAL REFRACTION. 
by dr. jamf.s Wallace; revised by dr. E. jackson. 

Emmetropia. — The normal eve produces a distinct image of 
external objects on the retina, particularly that portion of it 
situated at the posterior extremity of the visual axi-. 

The formation of the image is accomplished by the cornea, 
crystalline lens, aqueous humor, and vitreous humor. The 
cornea is the principal lens when the eye is at rest, as it separates 
two media with the greatest difference in density, and therefore 
has a higher refracting power than the crystalline lens. But the 
crystalline lens possesses the important function of accommoda- 
tion, and approaches during the maximum of this function very 
closely to the refractive power of the cornea. 

The cornea is not exactly spherical in curvature, but is an ellip- 
soid of revolution. In order to form a distinct retinal image, it 
is necessary that the curvature of the meridians should be sym- 
metrical ; any departure from this produces variations in their 
refractive power. The plane of the lens must be perpendicular 
to the visual line, and its different sectors must have a uniform 
density in the corresponding layers. The focal length of the 
dioptric apparatus of the eye must coincide with the length of the 
visual axis. 

The emmetropic eye has a range of vision from infinity to its 
near point. (See table, page 49.) Xo glass improves distant 
vision, and spectacles are not required for reading until the age 
of 45 or 50 years is reached. The average length of the emme- 
tropic eye is 22 mm., but it is possible for an eye to be emme- 
tropic with a longer or shorter axis, if the curvature of its lenses 
varies in proportion. 

Emmetropia, in the strict sense of the term, is the condition 
midway between hypermetropia and myopia, and its claim to 



140 DISEASES OF THE EYE. 

the title of normal refraction is denied, as it is not common to 
find people absolutely emmetropic. Experience shows that the 
more nearly an eye approaches to emmetropia the healthier are 
its membranes, and the more comfortable is its possessor in pro- 
longed exercise of this organ. No great departure from emme- 
tropia can exist without producing serious disturbance in the 
function of vision, and in the condition of the choroid and retina. 
One of the most important points in the treatment of eye diseases 
is to restore the eye to a condition of emmetropia by suitable glasses, 
and while this statement admits of modifications, in most cases it 
still remains the broad rule of practice. Anomalies of refraction 
lie at the root of 50 per cent, or more of all the diseases of the eye. 

Emmetropia is that refractive condition of the eye in which light 
is perfectly focused and the visual axis corresponds exactly ivith 
the focal length of the dioptric apparatus when at rest ; the far 
point lies at infinity, and the eye, in its condition of minimum re- 
fraction, is adapted to focus parallel rays on the retina. The 
principal focus, therefore, lies on the retina. 

When these conditions are not fulfilled the eye is said to be 
ametropia. 

Ametropia. — Ametropia is any departure from perfect focus- 
ing, or exact correspondence between the visual axis and the focal 
length of its dioptric apparatus when at rest. The principal focus 
is not a point or does not lie on the retiua. 

It is comprehensible that the dioptric apparatus may remain 
unaltered, while the eyeball increases or diminishes in length : 
this is denominated axial ametropia; or, the eyeball remaining 
unchanged in the length of its axis, the curvature of its lenses 
may undergo variations, constituting curvature ametropia. 

Ametropia is of three kinds. In the first class the refractive 
power of the eye is too weak, or the axis is too short, so that the 
principal focus of the eye falls beyond the retina. This is termed 
Hypermetropia, Hyperopia, or Far-sightedness. 

In the second class the refractive power of the eye is too strong, 
or the axis of the eye is too long, causing the principal focus to 
fall in front of the retina. This is termed Myopia, or Near- 
sightedness. 

The third class comprises Astigmatism. 



NORMAL AND ABNORMAL REFRACTION. 141 

It is convenient to distinguish the first two classes of ametropia 
by the relative position of the principal focus to the retina. 

Hypermetropia. — ffypermetropia is that fomi of ametropia in 
which the principal focus of the eye lies behind the retina. The 
visual axis of the eye is shorter than the focus of its lenses in their 
condition of minimum refraction. 

The far point of the eye is negative, and is represented by the 
point behind the eye, to which rays must converge, before enter- 
ing the eye, in order to be united on the retina. The refractive 
apparatus of the hypermetropic eye, in a condition of minimum 
refraction, is adapted to bring rays converging to this point to a 
focus on its retina. Rays passing out of a hypermetropic eye 
have a divergence as if they came from this point. 

The eyeball may be abnormally short, constituting axial hy- 
permetropia; a deficiency of 1 mm. in the length of the optic 
axis produces 3 dioptres of hypermetropia : or its refractive 
power may be deficient, curvature hypermetropia; an increase 
of 1 mm. in the length of the radius of curvature of the cornea 
produces a hypermetropia of 6 dioptres. 

Cause. — Hypermetropia is nearly always congenital, and 
nearly all eyes are hypermetropic at birth. The eyeball in- 
creases in length with the development of the rest of the body, 
and hypermetropia diminishes, passes into emmetropia, or, more 
rarely, into myopia. Eyes are said to become hypermetropic 
after 55 years of age ; but in many cases the hypermetropia has 
existed from early life, as latent hypermetropia, and now be- 
comes manifest at an advanced age. Senile changes in the crys- 
talline lens may produce the very opposite condition — myopia — 
as in the first stages of cataract. The extraction of the lens after 
cataract produces hypermetropia. 

Symptoms. — Hypermetropia renders it difficult to maintain 
a distinct image of small objects, e. </., printed matter, for any 
length of time : vision blurs, the subject is compelled to stop 
reading, and rub the eyes. This, for the moment, suffices to clear 
the vision ; but the trouble recurs again and agaiu, the accommo- 
dation becomes exhausted, and finally the work must be discon- 
tinued. The affected persons often hold a book or small objects 
in a strong light. The pupil in this way contracts, and vision is 



142 DISEASES OF THE EYE. 

rendered clearer. Many hypermetropic children hold their books 
close to their eyes, and, by contracting the palpebral fissures, are 
enabled to see better than with the book at a greater distance, 
because the object is seen under a larger visual angle, and the 
narrow slit between the lids cuts off the more divergent rays. 
These children are often erroneously supposed to be near-sighted, 
and concave glasses are given to them, which increase the trouble, 
instead of mitigating it. 

Hypermetropia often gives rise to sjmsm of the accommoda- 
tion, owing to the persistent contraction of the ciliary muscle 
necessary to overcome the error of refraction. This condition 
simulates myopia, and distant vision becomes indistinct. It 
may sometimes be improved by concave glasses, but these glasses 
should never be ordered, as they only aggravate the trouble ; 
hence the necessity of employing a mydriatic to reveal the true 
condition of the refraction. Spasm is prone to occur in individ- 
uals of neurasthenic condition ; it bears no relation to the vigor 
of the accommodation. The reverse is often true, that persons 
of relatively feeble accommodation have a marked cramp of the 
ciliary muscle. Spasm of accommodation is not, however, limited 
to hypermetropia. 

As a result of hypermetropia the coats of the eye become in- 
flamed. Conjunctivitis, blepharitis, and congestion of the retina 
and choroid are very frequent complications. Persistent head- 
ache, aggravated by using the eyes, various nervous symptoms, 
reflex in their nature, as well as disturbances in the visual func- 
tion, are the common results of hypermetropia (see also page 
543). Convergent squint nearly always is accompanied by 
hypermetropia. 

Hypermetropia is divided by Donders into manifest and latent. 
The manifest hypermetropia is represented by the strongest con- 
vex lens through which an eye, without the influence of a mydri- 
atic, retains distinct distant vision. The latent hypermetropia 
is the amount in excess of the manifest, developed by the action 
of the mydriatic. The manifest and the latent together form 
the total hypermetropia. 

Manifest hypermetropia is divided into facultative, relative, 
and absolute. Facultative hypermetropia may be overcome by 



NORMAL AND ABNORMAL REFRACTION. 143 

the accommodation without squinting; relative hypermetropia 
can be overcome by the accommodation only when the subject 
squints inward ; and absolute hypermetropia cannot be overcome 
by the accommodation. In early life manifest hypermetropia 
is usually facultative but in advanced age even hypermetropia 
of low grade becomes absolute. 

I > i : r BR M i nation of Hypermetropia. — Hypermetropia 
always exists : When distant vision is improved by a convex 
glass ; when the patient can read fine print through a convex 
glass at a greater distance than its focal length; when with the 
ophthalmoscope the interior of the eye, otherwise normal, is seen 
distinctly with a convex lens; and usually when the near point 
lies at a greater distance from the eye than is proper for the age. 
(See also Retinoscopy , page 132.) 

The presence of any or all of these conditions makes it proper 
to employ a mydriatic, for the purpose of uncovering latent hy- 
permetropia, unless the patient has reached his fiftieth year, at 
which age most of the hypermetropia is manifest. In young 
people, and in cases of spasm of the ciliary muscle or congestion 
of the choroid, it is often necessary to continue the use of the mydri- 
atic for a longer period than under ordinary circumstances, and 
at the same time to administer alteratives. 

Correction of Hypermetropia. — The principal focus F, 
of the hypermetropic eye, lies behind the retina. Consequently, 

Fig. 57. 




Far point of a hypermetropic eye. Rays from R on the retina of the hyperme- 
tropic eye after refraction diverge ; these rays, prolonged backwards, would unite 
at the point E'. R' is the far poiut. 

the retina R is situated within the principal focus, and its con- 
jugate focus or far point R' is virtual. (Fig. 57.) Rays from R 



144 DISEASES OF THE EYE. 

seem, after refraction by the eye, to have come from R' ; con- 
versely rays converging to R', after refraction by the eye, unite in 
R on the retina. The rays which come from the retina R, of such 
an eye, after emerging from the eye are divergent, and prolonged 
backward would unite in the point R'. The distance of this 
point from the cornea is the focal length of the glass which 
corrects the hypermetropia. The amount of divergence of the 
emergent rays is dependent on the degree of the hypermetropia, 
that is, the distance R lies in front of F. The higher the degree 
of hypermetropia is the farther R lies in front of F, and the 
nearer the point of divergence R' lies to R ; conversely, the lower 
the degree of hypermetropia is, the nearer the point R lies to F, 
and the farther back the point R' lies. The distance of R' must 
be less than infinity ; otherwise, the eye would be emmetropic. 
If parallel rays are given a convergence to the point R' by a con- 

Fig. 5s. 




Correction of hypermetropia by a convex glass. The lens L gives to parallel rays 
a convergence towards the point R'; they will consequently be united on the re- 
tina R' . R' is the virtual conjugate focus of R. 

vex lens placed before the eye, the rays will come to a focus at the 
point R on the retina, since the path of the rays passing into the 
eye after refraction by a convex lens (Fig. 58) is exactly the same 
as that of the rays diverging from the retina and passing out- 
wards (Fig. 57) ; only the direction is reversed. The far point R' 
of the hypermetropic eye is the point to which parallel rays must 
be given a convergence by a convex lens in order to come to a 
focus on the retina. The amount of this necessary convergence 
represents the deficiency between the refraction of the hyperme- 



NORMAL AND ABNORMAL REFRACTION. 145 

tropic and that of the emmetropic eve; the degree of hyperme- 
tropia is therefore in an inverse ratio to the distance of R'. 

To correct hypermetropia the refract inn of the eye must be 
increased by a convex lens of sufficient strength to bring F on 
the retina. This glass corrects the hypermetropia by shortening 
the focal length of the di optic apparatus to correspond exactly 
with the length of the visual axis. The far point R' is removed 
to infinity. Parallel rays come to a focus on the retina without 
any effort of accommodation, and rays emerging from the eye are 
rendered parallel. 

In order to neutralize the hypermetropia, that convex glass 
must be selected which gives the greatest visual acuity. As the 
greatest visual acuity is obtained when the retinal image is sharply 
formed, and as this occurs when rays are brought to an exact 
focus on the layer of rods and cones, the maximum visual acuity 
is the most satisfactory evidence that rays are exactly focused on 
the retina. If these rays are parallel, the glass which brings 
them to a focus on the retina corrects the hypermetropia. Rays 
from objects at 6 metres distance are sufficiently parallel for this 
purpose. 

The card of test letters, in good illumination, is hung on a 
wall, at this distance from the patient. A pair of trial frames 
is placed before the patient's eyes and one eye at a time examined, 
the other being screened by an opaque disc. The patient is sup- 
posed to have his accommodation paralyzed by a mydriatic, or to 
be beyond 50 years of age. He is required to read the smallest 
letters which he can see distinctly on the card. The resulting 
sharpness of vision is noted. Usually the degree of hyperme- 
tropia may be closely estimated by observing the diminution in 
visual acuity. A convex glass is now placed before the eye; this 
is stronger in proportion to the reduction of vision. If the con- 
vex glass improves vision, but does not raise it to normal, stronger 
lenses are tried until the one is obtained which yields the maxi- 
mum visual acuity ; or, if the stronger glasses do not improve the 
vision, successively weaker ones are tried until that glass is found 
which gives the greatest sharpness of sight. This is the lens which 
corrects the hypermetropia. If the acuity of vision is raised to 
normal by a convex spherical lens, it is not likely that astigma- 
10 



146 DISEASES OF THE EYE. 

tism is present, but every case should be examined with a view 
to discover any astigmatism. If none exists, the convex glass is 
all that is required to correct the ametropia. The examination 
should be repeated two or three times to insure accuracy. 

In the absence of a mydriatic and the presence of some ac- 
commodative spasm, vision being equal in the two eyes, a more 
suitable glass may often be obtained by testing both eyes simul- 
taneously, because with parallel axes the accommodation is more 
likely to undergo relaxation. This eifect may be further secured 
by placing a prism of 2° or 3° (centrads) before one eye with its 
base inwards. The effect of this is to relax the internal recti 
muscles and indirectly the accommodation. It is a good plan to 
begin by placing before the eyes a lens of stronger refraction 
than the one required, and gradually weakening it by concave 
glasses of successively higher numbers until normal vision is 
reached. The glass required is then the difference between the 
two. 

The proof that the glass selected is the correct one depends 
upon the ability of the patient to focus parallel rays on the retina. 
Parallel rays may be obtained by placing an object at the prin- 
cipal focal distance of a convex lens. The principal focal dis- 
tance of a 4-dioptre lens is 25 cm. Therefore, if the glass corrects 
the hypermetropia, the patient should be able to read fine print at 
25 cm. distance with + 4 dioptres added to his correction. If 
he reads at a greater distance than 25 cm., some hypermetropia 
is still uncorrected. If he reads at a nearer distance than 25 cm., 
the hypermetropia is probably over-corrected. 

The degree of hypermetropia may be determined by placing 
a convex lens before an eye whose accommodation is para- 
lyzed, and by finding the distance at which small type appears 
most distinct. Suppose the lens selected is 4 dioptres (focal dis- 
tance = 25 cm.), and that the patient reads best at 33 cm. Now 
33 cm. is farther than the principal focus, and the rays therefore 
are convergent after passing through the lens, since a 3-dioptre 
lens would render them parallel ; 4 dioptres =3 + 1 would give 
them a convergence of 1 D to the conjugate focus, 1 metre back 
of the eye ; one dioptre therefore represents the amount of the 
hypermetropia (see page 144). 



NORMAL AND ABNORMAL REFRACTION. 147 

Ride: Subtraci from the lens cm ployed, the lens whose focal 
distance equals the distance at which the patient reads. The 
difference is the degree of hypermetropia. 

It is often necessary to correct hypermetropia in children before 
they arc old enough to read. The ophthalmoscope and retino- 
scopy are the means upon which reliance is placed. The method 
of determining ametropia by retinoscopy is elsewhere explained 
(see page 128). 

After the degree of the hypermetropia has been determined, 
the very important question presents itself, what glass shall be 
ordered ? While the eye is under the influence of atropia, dis- 
tant vision is distinct with the full correction ; after the effects 
of the atropine have disappeared, it is often dim with the 
full correction, and a haze seems to lie over all distant objects 
which disappears when the glasses are removed. On the other 
hand, the headache, asthenopia, and congestive troubles return if 
the hypermetropia remains uncorrected. The spasm of accommo- 
dation is the disturbing factor in this problem, and it is so variable 
in different individuals that no precise rule can be given. Many 
people wear a full correction with comfort, and do not need any 
modification. On the other hand, others will tolerate but a small 
part of the correction, and then only after treatment by prolonged 
mydriasis, alteratives, and tonics. 

There are two methods of dealing with this difficulty. First, 
to order full correction while the eye is still under the influence 
of mydriatic, and to insist that this shall be worn constantly 
during the time that the accommodation is returning to its 
normal state. If, when the eye has regained its usual condition, 
in the course of from one to two weeks, the distant vision remains 
dim, the glasses may be weakened sufficiently to secure normal 
acuity of sight for long ranges. The instillation of eseriue will 
often assist in soothing the irritability of the ciliary muscle. It 
is not necessary to use this drug until a week or ten days after the 
mydriatic has been stopped. The strength employed is from 
gr. -^ to gr. ^ to the ounce of water, preferably the weaker solu- 
tion. 

It should be borne in mind, as Jackson insists, that the glass 
which gives the best correction at 4 or 6 metres is not the cor- 



148 DISEASES OF THE EYE. 

recting glass for the total H, but in reality is an over-correction 
of | to £ D. Strictly speaking, rays coming from those dis- 
tances are not parallel, and the glass which focuses them perfectly 
•on the retina will not perfectly i\)vu> parallel rays. Hence, in 
ordering a full correction, the glass which gives the best vision 
at 4 or 6 metres must be weakened by | or £ D. If this fact were 
more often remembered, less difficulty would be experienced in 
inducing patients to wear a full correction. 

Second, the eyes are first allowed to regain their full power of 
accommodation, and an interval of time, from one to two weeks, 
allowed to elapse after the atropine has been discontinued, and 
before the eyes are tried for the glass which is to be worn. The 
full correction is placed in the trial frame, and vision tested. If 
the patient has normal vision with the glass, it may be ordered. 
If the vision is reduced by the full strength of glass, the patient is 
ordered the glass nearest in strength to full correction with which 
he still has normal visual acuity. This may be only one-half, 
one-fourth, or even less, of the full amount. It is necessary in 
these cases to increase the strength of the glass from time to time 
as symptoms of fatigue manifest themselves. 

One very frequent cause of inability to wear a full correction 
depends upon insufficiency of the internal recti muscles (exo- 
phoria), causing an associated action of accommodation with the 
muscular effort necessary to bring the visual axes into a parallel 
condition (see also relative insufficiency of the intern i, page 542), 
The optical centres of the glasses require the greatest attention, 
and frequently need displacement slightly to the inside (see 
pasje 185). When the glass ordered for distance is only a small 
part of the full correction, it is very often Decessary to order 
another pair of lenses for reading which embodies nearly or quite 
the lull amount of correction. 

Some surgeons, instead of ordering the glass (nearest in strength 
to the full correction) with which the patient still has normal 
visual acuity, in each case systematically weaken the Lens which 
neutralizes the total hypermetropia by a given amount, usually 
0.75 D. Donders advised a glass based upou the manifest H, 
to which one-quarter of the latent II was added. Macnamara 
recommends, in absolute hypermetropia, the use of a convex 



NORMAL AND ABNORMAL REFRACTION. 11!) 

glass, the strength of which shall be equal to one-half of the sum 
of the manifest and total hypermetropia ; e. g. } manifest H = 
1.5 D ; total II = 3.5 D. H. m. + H. t. = 5 D; ordered + 
2.5 I>. The author, if convergence is ample, usually orders the 
full correction of II. If there i< exophoria, this plan must be 
modified, or the defect remedied by prisms or by prismatic ex- 
ercises. The indistinct vision, caused by full correction of H, 
due to a disturbance of the relative range of accommodation and 
convergence, may be overcome by systematically training the 
convergence (see page o44). 

Fig. 59. 




Angle gamma in hypermetropia. A, the optic axis. JV, the nodal point of 
lens. T" 31. the visual line, cuts the cornea at inner side of optic axis. N J", 
the angle gamma, in this case is positive. M, the macula. 

The visual line is often very much displaced to the inner side 
of the cornea in hypermetropia, causing a very large value of the 
angle gamma. 

Myopia. — Myopia is thai form of ametropia in which the retina 
/!>.-■ back of tht principal focus of the eye, and only those ray* which 
diverge from some point main- than infinity can come to a focus 
on the retina. This point is tin fur point of the myopic eye. 

The far point, therefore, is limited by the amount of divergence 
necessary to bring the focus of the ray- on the retina. The higher 
the degree of myopia is, the closer will the far point r lie to the 
eye. Rays coming from the retina converge to the far point and 
form there an image. (Fig. 60.) This image can be seen by the 
ophthalmoscope. The far point and the retina are conjugate 
foci. 'Sec page 131.) 

Cause. — Myopia may be produced by increased refraction of 
the cornea, or crystalline lens, curvature myopia, or by too great 



150 DISEASES OF THE EYE. 

a length of the optic axis, atrial myopia. In the great majority 
of cases myopia is due to elongation of the optic axis, often the 
result of pathological changes in the coats of the eye. 

Fig. 60. 




Far point of a myopic eye. Rays diverging from the retina c, will , after refraction, 
converge to r ; conversely, rays diverging from r, will, after refraction, converge 
to c ; r is the far point, r and c are also conjugate foci. 

Myopia frequently is progressive, and tl>e increased convergence 
rendered necessary by the near position of the far point is a sig- 
nificant factor in the further production of myopia on account 
of the distention backwards which results from the compression 
of the ball between the external and internal rectus muscles. 
The sections of myopic eyes show a thinning posteriorly of the 
sclerotic and choroidal coats, proving that the elongation of the 
axis is due to a stretching of the coats of the eye. The choroid 
also gives evidence of being drawn towards the temporal side, 
producing a crescentic space at the outside of the nerve of a 
whitish hue, known as conus, or myopic crescent. The optic nerve- 
head is often distorted in the same direction. AVeiss and Ran- 
dall have described a curvilinear reflex, generally at the nasal side 
of the optic disc, as a prodromal sign of myopia. 

Myopia is also occasioned by changes in the shape of the cornea 
as a result of disease. Conical cornea, by increasing the curva- 
ture as well as lengthening the axis, gives rise to myopia. 

The principal theories which have been urged to explain the 
production of myopia are : — 

(1) The Anatomical Theory, which ascribes the production of 
myopia to the incentive given by the shape and size of the orbit 
to greater development of the eyeball. The size of the orbit is 
usually dependent on the conformation of the face. 



NORMAL AND ABNORMAL REFRACTION. 151 

(2) The Mechanical Theory, which ascribes the development of 
myopia to the compression of the eyeball by the muscles (the ex- 
ternal rectus) producing distention of its coats backwards by the 
excessive convergence rendered necessary at the close distance at 
which myopes work. In such cases the external rectus winds 
around the eyeball like a hand. 

According to Stilling, the superior oblique is the principal mus- 
cle which compresses the eyeball in myopia, and he thinks the low 
position of the trochlea increases the amount of force which this 
muscle exercises on the globe. This position occurs because of 
the diminished vertical diameter of the orbit in myopes, and, 
on this account, he believes he can predict in childhood those 
who will become myopic. Schmidt-Rimpler, on the other hand, 
declares that the vertical diameter of the orbit is higher in my- 
opia than in hypermetropia, and rejects Stilling's conclusions. 
Stilling's hypothesis, which is a combination of the anatomical 
and mechanical theory, leads to the conclusion that myopia is a 
question of race ; that the broad, low face of the German, for 
example, contains the conditions for the production of myopia, 
while the long, narrow face of the English or American disposes 
toward hypermetropia. The influence of race is also mentioned 
by Landolt, who says : " It is evident that myopia will be 
developed more rapidly in eyes that are already relatively long, 
i. e.j em met ropes and slight myopes, such as we find with a de- 
velopment of the skull in the antero-posterior diameter ; thus, 
race becomes a factor, etc." 

(3) The Inflammatory Theory. — The frequent observation by 
Graefe and others of choroiditis in the posterior portion of the 
eyeball, of areas of pigment absorption, and changes in the 
vitreous humor, has given rise to the belief that the existing 
sclerotico-choroiditis is the essential factor in the production of 
myopia. These inflammatory changes are traced to habits of life 
which promote fulness of the veins of the head and neck and hin- 
der the egress of the blood from the eye, such as bending over a 
desk during study, as a result of disparity between the height 
of th<- desk and the size of the child, or from working in rooms 
with insufficient illumination. Plethora might in the same way 
dispose toward- congestion of the eyes. Sluggishness of the 



152 DISEASES OF THE EYE. 

circulation, insufficient exercise in the open air, confinement in 
badly ventilated rooms, may easily increase the myopia, if they 
do not originate it. The fluids of the eye are increased in 
amount, the sclerotic becomes softened from inflammation and 
yields to the pressure from within. It is probable that this 
is the cause of a number of the cases of progressive myopia. 
Batten believes that myopia is an inherited tendency, its com- 
mencement and increase being caused by general aud local vas- 
cular congestion, in their turn the result of constitutional dis- 
turbance, for example, cardio-vascular disease. Malignant pro- 
gressive myopia is always characterized by notable changes in 
the fundus oculi (page 155). An acute posterior sclerotico- 
choroiditis may occasion a myopia in any eye. 

Although prolonged use of the eyes at near work explains the 
acquisition of myopia in many cases, only a fraction of those sub- 
jected to such a strain become myopic. Therefore in this num- 
ber, as Fuchs remarks,- special additional factors must be present : 
predisposition, too great approximation of the work, exophoria, 
and spasm of the accommodation. 

The defenders of the mechanical theory consider the choroiditis 
a secondary result. Those who regard the choroiditis as the 
initial stage of the process, consider the lengthened axis to be the 
result of the inflammation. 

The largest number of myopes are found among the upper 
classes, and among artisans whose work demands close inspection ; 
but the highest grades of myopia may exist among the lower 
classes, who do not use their eyes for close work and have been 
free from the influence of school life. Thus, Donders has seen 
the highest grades among sailors and peasants, and other ob- 
servers confirm this statement. Forster calls attention to the fact 
that myopia may be produced at home, and not in the school, if 
children are allowed to prepare their evening lessons when seated 
around a table which is too high for them, or which is imper- 
fectly or improperly illuminated, or if the children are allowed 
to study in dark portions of the room and hold their books close 
to their faces. 

Myopia is said to be more prevalent among Jews than among 
Christians of the same social class (Sydney Stephenson). 



NORMAL AND ABNORMAL REFRACTION. 153 

Among other causes of less significance may be mentioned 
unusually great distance between the pupils, rendering conver- 
gence more difficult; divergent squint and a large size of the 
angle gamma, in this case negative, also throw more strain on the 
eve muscles in convergence. 

It is conceivable that after myopia is once produced, the eye- 
ball, by its oval shape and greater size, may act as a cause of its 
further development by the increased muscular effort necessary to 
rotate such a ball inwards during convergence, and the compress- 
ing effect of the external recti muscles on the increased posterior 
segment of the ball. The strain on the accommodation has been 
urged as a cause, but as myopes accommodate less than others, 
this argument loses much of it weight. The influence of hered- 
ity is felt here, as elsewhere. Persons with myopic ancestry 
seem to have a tendency towards myopia. 

Myopia, rarely congenital, usually makes its appearance from 
the eighth year upwards, and sometimes is ascribed to a febrile 
attack. It is often the continuation of a process started in hyper- 
metropic eyes, especially those with astigmatism, and the gradual 
transition from hypermetropia to myopia is not infrequently seen 
among patients who return for re-correction. 

The prevalence of myopia in this country is distinctly less 
than in Europe. It is especially frequent in Germany, in the 
higher classes of the schools reaching, according to Cohn, 60 per 
cent. In a study of 200,000 eyes, Risley has observed an arrest 
of the increase of myopia as the result of treatment and the 
optical correction of ametropia. 

Symptoms. — The symptoms of myopia range themselves under 
the two classes : subjective and objective. 

The subjective symptoms are those which naturally arise because 
the range of vision is limited by a radius of a few centimetres. 
Distant objects are not clearly perceived ; the myope is surrounded 
by a fog. As soon as an object passes beyond his far' point it 
becomes indistinct. He must either bring objects to his eyes in 
order to see them clearly, or else walk up to the objects. 

.Myopes have au inclination to avoid out-door sports on account 
of their poor vision, and exhibit a greater fondness for occupa- 
tions which come within their range, e. g., reading, drawing, etc., 



154 DISEASES OF THE EYE. 

than for others which require good distant vision. The prolonged 
congestion of the eyes which such habits entail leads to increase 
in the myopia. Headache and reflex phenomena are unusual 
accompaniments of myopia, unless complicated with consider- 
able astigmatism. Myopia, however, frequently causes aching of 
the eyeballs, very imperfect ocular endurance, congestion of the 
conjunctiva — indeed, many of the symptoms which are strictly 
asthenopic, especially when the choroid is undergoing the changes 
which are determining the increase in the refractive power. 

The objective symptoms of high myopia may embrace: (1) 
The prominent eyeball. (2) A somewhat stupid expression of 
the countenance from inability to note the expression in the face 
of others. (3) A peculiar manner of reading. The book is held 
stationary, and the face is moved from side to side following 
each line. (4) The enlarged optic disc, seen in the direct method, 
by placing concave glasses in the ophthalmoscope; and the in- 
verted image of the fundus, obtainable by withdrawing the mirror 
some distance from the eye. (5) Divergent squint. This is fre- 
quently a sign of myopia. The squinting eye is often amblyopic. 
Binocular vision does not exist in such a case ; the good eye, freed 
from the necessity of convergence, reads at the far point without 
any effort, and glasses for reading are sometimes unsatisfactory 
because the print appears smaller on account of its removal to a 
distance greater than the far point of the eye. If the acuity of 
sight is much diminished, this becomes a serious difficulty in the 
use of glasses, notwithstanding the increased area of vision which 
they afford. 

The visual axis in myopia sometimes passes through the cornea 
at the outer side of the optic axis ; the angle gamma is then nega- 
tive, and the eye in looking at a distant object turns inwards in 
order to bring the visual line to fix on it, giving rise to an ap- 
parent convergent squint. (Fig. 61.) This renders necessary a 
greater degree of convergence. 

Myopic eyes are popularly considered as strong eyes, from the 
fact that they see fine print at close distances. This is true only 
in those cases in which the tunics of the eye have suffered no in- 
jury — where, for example, the myopia is of moderate degree and 
not due to disease. 



NORMAL AND ABNORMAL REFRACTION. 155 

Myopia does not usually decrease with age, but, ou the con- 
trary, tends to increase up to adult life or later. 

The higher degrees of myopia (malignant myopia) are marked 
by ravages in the structure of the choroid and retina. The pig-* 

Fig. 61. 




Angle gamma in myopia which is negative. 

ment-cells wander off in some places and accumulate in others, 
producing marked contrasts in the appearance of the eye-ground. 
Large areas of atrophy, glistening white in color, alternate with 
black splotches, and at times hemorrhages occur. The disc is 
often surrounded by an atrophic area, the posterior staphyloma. 
The vitreous humor is semi-fluid, and floating opacities are often 
visible, sometimes being so large as to obscure vision. Owing to 
the intimate relation between retinal nutrition and the pigmented 
epithelium of the retina, the loss of the latter is followed by 
diminution in the visual acuity. In higher grades of myopia — 
15 to 20 dioptres, and sometimes still higher — the condition of 
the eye is very desperate, and the morbid processes may culmi- 
nate in detachment of the retina and complete blindness. 

The ciliary body is feebly developed in myopia of considerable 
degree, as a result of which accommodation is often much dimin- 
ished, and the anterior chamber is larger. For this reason the 
tendency to glaucoma in myopic eyes is said to be lessened. 

Determination and Correction of Myopia. — Myopia 
may be determined : (1) By the position of the punctum proxi- 
mum of accommodation, which is closer to the eye than is nor- 
mal for the age. (2) By the position of the farthest point of 
distinct vision obtained by test-types. (3) By the ophthalmo- 
scope and retinoscope. (4) By the concave glass which gives 



156 



DISEASES OF THE EYE. 



distinct vision at a distance of 6 metres. In all these methods 
we seek to obtain the degree of myopia by the amount of diverg- 
ence which must be given to rays to enable them to meet on the 
retina. 

In the myopic eye, only those rays which diverge from a dis- 
tance not greater than the far point can be focused on the retina. 
In order to see at any greater distance than this the rays must 
be given a divergence as great as if they came from this point. 
(Fig. 62.) If the greatest distance at which a myopic eye can 

Fig. 62. 




Manner in which concave lens causes rays to diverge from the far point of a 

myopic eye. 

see fine print is 14 cm., in order to see at a still greater distance 
the eve would require a concave glass which would give rays a 
divergence as if they came from this point. By dividing 100 
by 14 we obtain the number of dioptres (7) necessary to produce 
this divergence. 

In order to secure accuracy, it is necessary to bear in mind, as 
the far point is measured from the cornea, that the glass must be 
placed close to the cornea ; if the glass is removed 1 cm. from the 
cornea, it is plain that its focal point will also be one centimetre 
farther away ; therefore it is necessary to employ a glass of 
shorter focus. 

Example.— Suppose it is desired to cause the rays to diverge from a 
point 14 cm. in front of the cornea, and the glass is to he placed at 1.5 
cm. in front of the cornea : it is evident, under these circumstances, 
that the glass would require to have a focus of 14 —1.50 = 12.5 cm., or 

100 ,. , 

= 8 dioptres. 

12.:. l 

The usual position for a glass is about 13 mm. in front of the cornea. 



NORMAL AND ABNORMAL REFRACTION. 157 

In low degrees of myopia this does not affect appreciably the 
strength of the glass", but in the higher degrees it makes a serious 
difference. The concave glass is therefore somewhat stronger than 
the actual myopia, especially in the higher grades. 

The degree of myopia may be determined approximately by 
this method more rapidly than by beginning the trial at 6 metres 
with glasses (in this instance, eoncave) in the manner described 
in connection with hypermetropia. One example will suffice: — 

A patient reads tine print distinctly at 8 cm. from the cornea, but 
not at ;i greater distance ; the eye being under the influence of atro- 
pine, this is his far point. In order that he may see at an infinite dis- 
tance, parallel rays must be given a divergence as if they came from 8 
cm. in front of the cornea. As the glass will be placed 13 mm. in 
front of the cornea, its focal length must be 8 cm. — 1.3 cm. = 6.7 cm., 

or 07 mm. — — ■ mm. equals 15 dioptres, as the number of the concave 

lens required to permit distant vision. A lens of this number should 
be placed in the trial frame, and the vision determined through it by 
means of test-types at the usual distance. Perhaps a weaker or 
stronger lens may give better vision, and hence several numbers 
should be tried in succession, until that glass is selected with which 
the greatest acuity of vision is attained, and which then represents the 
correcting lens. 

A patient often will select a glass of higher number than the 
one really required, because the letters have a blacker and 
sharper appearance when seen through concave lenses ; but 
unless the stronger glass at the same time secures for the 
patient an increased acuity of vision, it should be rejected, and 
the weaker lens adopted. If several lenses give equally good 
vision, the weakest one should be chosen. 

The method of determining the correcting lens in myopia by 
means of ophthalmoscopy and retinoscopy is elsewhere described. 
(See pages 117 and 128.) 

The position of the lens used to correct high grades of myopia 
is of great importance. The nearer the lens is placed to the 
cornea the stronger it becomes ; conversely, the farther it is re- 
moved from the cornea the weaker it is. The strong concave 
lenses necessary to correct high degrees of myopia in this May 
may sometimes be utilized by the patient to gain artificial accom- 



158 DISEASES OF THE EYE. 

modation. By bringing them close to the eye, vision is adapted 
for distance ; by pushing them from the eye, divergence is lessened 
and the eye is adapted for a closer point. 

The visual acuity in high myopia is usually reduced, and iu 
those cases accompanied by changes in the retina and choroid 
this reduction assumes a considerable grade. Sometimes very 
slight improvement in distant vision is secured by concave 
glasses, and near vision may not be at all benefited. Under 
these circumstances patients see better by using one eye alone 
and bringing the print or other work close to the eye, because 
the enlarged retinal image compensates for the diminished visual 
acuity. These cases, however, are seldom encountered, and a 
concave lens, properly selected, almost always improves both 
near and distant vision. 

Hence the treatment of myopia consists in the selection of suit- 
able concave glasses, the object of which is to remove the far 
point sufficiently distant to prevent too great convergence, and 
at the same time demands the recognition and correction of any 
co-existing astigmatism. 

In so far as the development of myopia is due to pernicious 
methods of reading and study, its prophylaxis should include at- 
tention to the following points : The correct position of the head 
and body during study ; the employment of books with suffi- 
ciently large and distinctly printed type ; and good illumination 
coming from behind the patient, preferably over the left shoulder. 
The reading-desk should be tilted upwards, so that the page may 
be parallel with the face, thus obviating the necessity of craning 
over the desk. The hours of study should be restricted within 
reasonable limits, and they should alternate with periods of rest 
and exercise, or employment in the open air. 

It is during school-life, from the eighth to the eighteenth 
year, that myopia makes its progress. The illumination of the 
school-room, its ventilation, the proper height of the seat both 
in relation to the desk and to the floor, the correct slope of the 
desk, the size of the type in the school-books, and the hours of 
study, have all been carefully arranged with a view towards 
removing disposing causes. It is said that in Germany myopia 



NORMAL AND ABNORMAL REFRACTION. 159 

has already beeE diminished <> per cent, by these hygienic mea- 
Bures. ( Von Elippel.) 

[f a tendency to divergence exists in early life, it is sometimes 
proper to remove this by tenotomy of the external rectus as a 
preventive measure against the development of myopia. 

( Ordering of Glasses. — Afterthe estimation of the degree of 
myopia, the existence of astigmatism having been excluded, or, 
if present, corrected, the strength of the glass suitable for constant 
use. reading, or other special work must be determined. This is 
decided by the visual acuity, the range of accommodation, and 
the degree of the myopia. 

Young people (under 20), with good vision and a moderate de- 
gree of myopia (under 5 D), may wear the full correction con- 
stantly if the accommodation is ample and no signs of fatigue are 
evident. In higher grades of myopia associated with lowered 
vision, it is often necessary to diminish the full correction from 
1 to 3 dioptres. It is evident that the greater the visual acuity, 
the farther away the same size of type can be seen ; hence the 
demand on accommodation is less as the visual acuity is greater. 

As age advances, an additional glass should be ordered for read- 
ing which will give the patient a far point of from 30 to 60 cm. 
In order to obtain this, the full correction must be diminished 
from 1.50 to 3 dioptres. 

When strong concave lenses are first worn, a lack of accommo- 
dation often appears, which is restored by a few months' use of the 
glasses. For the relief of this deficiency it is advisable to give a 
partial correction for near work until ample power of accommoda- 
tion is gained, when the full correction may be used for all purposes. 

Full correction is the object to be attained for young persons 
with normal visual acuity and binocular near vision, no matter 
how high their myopia (Jackson), provided the lens selected shall 
not be an over-correction when brought close to the eye. When 
visual acuity i.^ imperfect or binocular vision lost, it is better to 
order a partial correction for near work. When wearing a partial 
correction the patient is tempted to improve distant vision by 
looking obliquely through the glass. But this gives it a cylin- 
drical effect, varying with the direction of the visual axis, and 
i- always injurious. 



160 DISEASES OF THE EYE. 

Concave glasses diminish the size of the retinal image, especially 
when the glass is removed farther from the eye. The retinal 
image is larger in myopia than in emmetropia, but, if the correcting 
lens is exactly 13 mm. in front of the cornea, the image is of the 
same size as in emmetropia. 

Concave lenses act as prisms when the visual line passes through 
any portion except the optical centre. The optical centres should 
always be separated by a space equal to, and never less than, the 
inter-pupillary distance, except in those cases of weakness of the 
internal rectus muscles where it is advisable to increase the dis- 
tance between the centres. This produces the effect of a prism 
with its base inwards, that is, it lessens the amount of convergence 
which otherwise would be required. The deviation may be cal- 
culated from the focal distance of the lens, and the amount of de- 
centering. The distance the optical centre is displaced, divided 
by the focus, equals the tangent of the angle of deviation. 

The painful glare of light sometimes caused by wearing con- 
cave glasses may be modified by tinting them. 

Since Fukala's recommendation removal of the crystalline 
(discission, followed by extraction) has been practised by a 
number of operators for the relief of high myopia (15 D or 
more). Improvement in vision and increase in the distance at 
which eyes can be used in near work are claimed as the results 
of successful operations. 

The reading-glasses for myopes are described under Presby- 
opia. 

Astigmatism. — In the preceding forms of ametropia, H. and 
31., the cornea has been considered as an ellipsoid of revolution, 
so that planes passing through it in various directions, vertical, 
horizontal, and oblique, produce sections having an equal curva- 
ture. Equal refraction consequently takes place in these different 
planes. Variations in the curvature of the different meridians 
produce differences in their refractive power ; in some of these 
meridians the eye must therefore be ametropia Three conditions 
may arise : — 

I. The eye may be emmetropic in one meridian and ametropic 
(either H. or 31.) in the others. 

II. The eye may be ametropic (H. or 31.) in all meridians, 
but in different decrees. 



NORMAL AND ABNORMAL REFRACTION. 161 

III. The eye may be ametropic in all meridians, but in some 
11. and in others .1/. (H. and .1/.). 

It is convenient to designate the different parts of the eye by 
imaginary lines, similar to those employed in geography. 

The oasis of the eye is a line drawn from the centre of the cor- 
nea through the centre of the ball. Passing through the centre of 
the lens and the centre of rotation, it penetrates the sclerotic 
between the optic nerve entrance and the macula. The anterior 
and posterior extremities of this line are the poles of the eye. 

A great circle extending round the ball perpendicularly to the 
axis, and at an equal distance from the two poles, is called the 
equator of the eye ; other great circles passing through the poles 
are called meridians. 

The lens is described in a similar way by its axis, anterior and 
p< tsterior poles, and equator. 

When the meridians of the cornea have an equal curvature, the 
rays of light gather in one common focus. Frequently, the 
cornea has meridians of unequal curvature producing greater re- 
fraction in some meridians and less in others. The rays passing 
through the meridians of highest refraction reach their focus 
soonest, while those passing through the less refracting meridians 
come to a focus farther back. 

Definition. — The term Astigmatism is applied to that refrac- 
tive condition of the eye in which a luminous point, for example a 
star, forms an image on the retina, the shapje of which image is a 
line, an oval, or a circle, according to the situation of the retina, 
but never a point. 

Seat of Astigmatism. — Usually the cornea is the seat of 
astigmatism, but astigmatism may also be produced by an oblique 
position of the lens, or by the visual line passing eccentrically 
through the cornea. 

When the meridians of the cornea progress evenly in their re- 
fraction from the lowest to the highest, the astigmatism is termed 
regular. When the curvature in different parts of the same meri- 
dian varies, and the meridians vary irregularly in their curva- 
ture, as the result of cicatrices from ulcers, or distention of the 
cornea from inflammation, the astigmatism is called irregular. 

Almost all eyes possess more or less irregular astigmatism. 
11 



162 



DISEASES OF THE EYE. 



Usually it is only slight, and gives no serious inconvenience for 
ordinary vision, but all points of light, such as stars, distant street 
lamps, etc., shoot out rays and twinkle as the result of the irregular 
astigmatism of the eye. The seat of this irregular astigmatism is 
in the crystalline lens. In the lenses of young people the union of 
the sectors is visible by three faint lines — the lens-star (Fig 63); 

Fig. 63. 




Spectrum of lens showing sectors. (Donders.) 

in the adult, secondary rays are also visible. Slight differences 
in the density of the several sectors are sufficient to produce a dis- 
torted image of a luminous point. 

Principal Meridians. — In regular astigmatism the cornea 
has one meridian with the shortest radius of curvature producing 
the highest refraction, and another meridian, at right angles to 
this, with the longest radius of curvature, and the least refraction. 
These are called the principal meridians, and may be situated in 
any part of the cornea, but there is a disposition of the most 



NORMAL AM) ABNOBMAL REFRACTION. 163 

refracting meridian to lie in or near a vertical direction, and of 
the least refracting meridian to lie in a horizontal direction. 

To simplify the phenomena of astigmatism the principal me- 
ridians will be considered as running vertically and horizontally 
with the greatest refraction in the vertical, and the least refraction 
in the horizontal meridian. It must be borne in mind that these 
meridians may be inclined to the perpendicular, or even reversed. 

Form of the Image of a Point Focused by an Astig- 
matic Eye. — The rays passing into an astigmatic eye, thus con- 
sidered, are most sharply refracted by the vertical meridian. 
The bundle of rays, instead of having a round section, forms 
a horizontal oval, which becomes smaller as the rays travel 
farther backwards; but the vertical diameter of the oval lessens 
mi «t rapidly until, when the focus of the vertical meridian is 
reached, the figure becomes a horizontal line, because all the 
rays are brought to one level and remain diffused only in the 
horizontal direction. 

Farther back the rays, after passing this focus and crossing, 
diverge again vertically, and the figure becomes once more a hori- 
zontal oval ; but shorter because the horizontal diffusion is 
diminished. 

Still farther, the figure assumes the form of a circle; the 
diffusion of the horizontal rays has become less, and that of the 
vertical rays more. The figure becomes next a vertical oval, 

Fig. 64. 



)h &—£-&' h-^-H ##**' h^rh' Ah ti- 
ts i, '■':■' \ 



Retinal images of a point in the different forms of astigmatism. A, compound 
hypermetropic astigmatism. B, simple hypermetropic astigmatism. I) E, 
mixed astigmatism. F, simple myopic astigmatism. G, compound myopic 
astigmatism. 

then a vertical line as the focus of the horizontal meridian is 
reached. Finally,, the section is again a vertical oval, the hori- 
zontal rays, having passed their focus, cross, and begin to 
diverge. (Fig. 64.) 



164 DISEASES OF THE EYE. 

It is evident from this that no matter what position the retina 
may occupy, no distinct image can be formed upon it, but there 
must always be overlapping of the images of the different points 
of an object, causing a blur or a wrong impression of its outline. 

Symptoms. — In this manner the acuteness of vision is dimin- 
ished by astigmatism. Letters are not distinctly seen, some let- 
ters being confused with others — H and N, B and S, F and P, 
K and X, V and Y. The overlapping of the diffusion areas 
in the retinal image produces, in high degrees of astigmatism, 
an apparent doubling of the object. The indistinctness of vision 
compels a closer approximation of the object, with a consequent 
strain upon the accommodation. 

Astigmatic people learn to overcome their astigmatism by con- 
tracting the lids close together in order to make a horizontal slit. 
The vertically divergent rays are thus excluded, and the eye, ac- 
commodated for the horizontally divergent rays, receives a more 
distinct though fainter image. There is an almost characteristic 
facial expression in astigmatism caused by contraction of the lids. 

Astigmatism produces an indistinctness in the appearance of 
fine lines running in certain directions, the direction of the in- 
distinct lines being determined by that meridian which has its 
focus on or nearest to the retina. This meridian, therefore, will 
most nearly approach emmetropia ; the lines parallel to it will 
appear indistinct, while those parallel to the opposite meridian, 
or the one farthest removed from emmetropia, are most distinctly 
seen. 

In those cases in which the horizontal meridian is emme- 
tropic, and the vertical meridian ametropic, fine parallel lines 
running in a horizontal direction will appear spread out into 
thick bars, while vertical lines will appear distinct. 

To understand this, the student should remember that rays 
diverge from a horizontal line in all directions; those which pass 
through the horizontal meridian, if they are not exactly focused, 
spread out in the direction of the line, causing its extremities to 
appear somewhat faint in outline, but do not blur its width. 
The rays which diverge in vertical planes from the different 
points in the line pass through the vertical meridian. If this is 
not emmetropic, the breadth of the line appears thicker; but if 



NORMAL AND ABNORMAL REFRACTION. 



165 



the vortical meridian is emmetropic it forms a distinct point in 
the image, of each point in the object, by bringing the rays which 
pass through it to a focus. A horizontal line thus appears as a 
succession of distinct points when the vertical meridian is em- 
metropic. Vertical lines, in the same way, appear most distinct 
when the horizontal meridian is nearest to emmetropia, or if 
oblique lines appear most distinct, the meridian at right angles 
to their direction is the one nearest to emmetropia. Luminous 
points are drawn out in the direction of the ametropic meri- 
dian, and luminous circles become elongated into ovals. Astig- 
matism may be responsible for the most aggravated types of 
asthenopia. Fully sixty per cent, of functional headaches are 
caused by this type of refractive error, either alone or in associa- 
tion with other forms of ametropia. The headache may vary 
from a moderate frontal distress to violent explosions of pain, 
and may be situated in any portion of the cranium. Further- 
more, all the symptoms detailed on page 543 are the frequent 
result of astigmatism, not only when the error is of high degree, 
but commonly, indeed, more commonly, when it exists in low 
grade, and often unassociated with any symptoms which prom- 
inently direct attention to the eyes as the cause of the distress. 

Regular Astigmatism. — Regular astigmatism is classified 
into five varieties, according to the relative position of the retina 
to the foci of the two principal meridians. The horizontal meri- 
dian focus is represented by H., the vertical meridian by V. 



Fig. 65. 



Fig. 66. 





Foci of the principal meridians in 
simple hypermetropic astigmatism. 



Foci of the principal meridians 
in simple myopic astigmatism. 



1. Simple hypermetropic astigmatism. — In this variety one me- 
ridian, usually the vertical, is emmetropic, and the horizontal 
meridian is hypermetropic. The focus of the vertical meridian 



166 



DISEASES OF THE EYE. 



is on the retina, the focus of the horizontal meridian is behind 
the retina (Fig. 65) ; horizontal lines appear distinct. 

2. Simple myopic astigmatism. — The focus of one meridian, 
usually the horizontal, is situated on the retina, while the focus 
of the vertical meridian lies iu front of the retina. The vertical 
meridian is myopic, and the horizontal meridian emmetropic 
(Fig. 66); vertical lines appear distinct. 

3. Compound hypermetropic astigmatism. — All meridians are 
hypermetropic, but usually the horizontal presents the greatest 
ametropia. The focus of each principal meridian is situated back 
of the retina, that of the vertical generally being nearest to it 
(Fig. 67) ; horizontal lines are usually most distinct. 

4. Compound myopic astigmatism. — All meridians are myopic, 
but the vertical presents the greatest ametropia. Both principal 



Fig. 67 



Fig. 68. 





Foci of the principal meridians in 
compound hypermetropic astigmatism. 



Foci of the principal meridians 
in compound myopic astigmatism. 



Fig. 69. 



meridians have their foci in front of the retina, that of the hori- 
zontal lying closer to the retina (Fig. 68) ; vertical lines are usu- 
ally most distinct. 

5. Mixed astigmatism. — The retina lies between the foci of the 
two principal meridians. The hori- 
zontal meridian is hypermetropic, and 
the vertical meridian is myopic (Fig. 
69) ; no lines appear distinct, unless 
the eye simulates myopic astigmatism ; 
in this case the vertical lines appear 
distinct. 
Recognition of Astigmatism. — 
„ . „ Astigmatism is recognized subjectively 

Foci of the principal men- ° . 

dians in mixed astigmatism, by the greater distinctness ot lines 




NORMAL AND ABNORMAL REFRACTION. 167 

which run in one direction, and the blurring of those lines which 
run in a direction at right angles to this. The vertical strokes of a 
letter may appear distinct, while the horizontal strokes are hazy. 
The figures od a clock dial sometimes appear more distinct at 12 
and 6 than at 3 and 9, or any other two directions which are 
perpendicular to each other. For this reason astigmatic patients 
have sometimes imagined that their vision is better at certain 
hours of the day than at others. (Carter.) 

A diminished visual acuity, unimproved by spherical lenses, in 
the absence of organic disease, usually is due to astigmatism. 
Patients frequently complain that letters have a streaked or 
smeared appearance. Small gas flames seem to be drawn out 
in one direction. 

Astigmatism is recognized objectively, and its degree very 
closely estimated, by the ophthalmoscope, the ophthalmometer, 
and retinoscopy. 

The optic disc has a characteristic appearance in astigmatism ; 
its round appearance is altered to an ellipse, which is more 
elongated as the degree is greater. It appears as if a brush 
had been swept across it in the direction of its long axis ; the 
retinal vessels appear in focus only in one direction at a time, 
and convex or concave glasses must be added to the ophthalmo- 
scope to bring the other vessels into focus. 

The long axis of the optic disc is usually vertical, and the 
vertical vessels appear as the most hypermetropic or least my- 
opic, although the refraction of these meridians is just the 
opposite. 

The explanation of this is, that the breadth of the vertical ves- 
sels is focused by the successive horizontal meridians. When 
the horizontal meridians are emmetropic, the vertical vessels 
appear distinct ; consequently, if the vertical vessels are seen 
most distinctly with + 6 D, the horizontal meridian has a 
hypermetropia of that degree ; or, if the horizontal vessels are 
most distinctly seen with — 2D, the vertical meridian has a 
myopia of that amount. The horizontal vessels are focused by 
the successive vertical meridians. 

The disc is elongated in the direction of the meridian of greatest 



168 



DISEASES OF THE EYE. 



curvature. The longer and shorter axes of the oval thus corre- 
spond with the principal meridians of curvature. 

In order to estimate astigmatism with the ophthalmoscope, find 
the lens which gives a distinct image of the vessels running in 
the direction of the long axis of the oval ; and then, in a similar 
way, find the glass with which a distinct image of the vessels at 
right angles to the first is obtained ; the difference in refractive 
power between these two glasses is the degree of astigmatism. 
The ophthalmoscope must be brought close to the eye, and the 
strongest convex or the weakest concave lens is the measure of 
the ametropia. 

In cases of compound hypermetropic astigmatism, both vertical 
and horizontal vessels are seen with a convex lens ; but the vertical 

Fig. 70. 




Focusing of the vessels by the meridians of an astigmatic eye ; the parallel 
lines on each vessel represent the direction of the meridians through which a dis- 
tinct image of the vessel is obtained. 

vessels are clearly seen with a stronger lens than the one with 
which a clear image of the horizontal vessels can be obtained. 
The difference between the two glasses represents the degree of 
astigmatism. 



NORMAL AND ABNORMAL REFRACTION. 109 

In compound myopic astigmatism, the vessels of both principal 
meridians are seen distinctly with concave lenses, but those which 
run in the horizontal direction usually require the strongest glass. 
The difference between the two glasses represents the degree of 
astigmatism. 

When the vertical vessels are most distinctly seen with a con- 
vex glass, and the horizontal vessels with a concave glass, the 
astigmatism is still the difference between the two meridians ; 
but, as the refraction in one meridian is positive, and in the other 
negative, the difference is represented by the sum of the two 
glasses. Thus, vertical vessels 4- 1.50 D and horizontal vessels 
— ID, would represent an astigmatism of 2.50 D. (Compare 
also page 121.) 

In the indirect method of ophthalmoscopy, the astigmatic disc 
appears oval, but the long and short axes are reversed in direction 
when the auxiliary lens is held close to the eye. On removing 
it farther, the diameters change ; the longer diameter becomes 
shorter, or the shorter becomes longer, or one diameter becomes 
shorter while the other grows longer, so that the oval is again 
reversed. (Compare also page 126.) 

The ophthalmometer of Javal permits measurement of the cor- 
neal astigmatism by means of the changes which take place in 
the size of the reflected images of two test objects, on account of 
variations in the curvature of the corneal meridians. One im- 
portant point in favor of this instrument, and one of its great 
advantages over the ophthalmoscopic determination of astigma- 
tism, is that variations of accommodation in the patient's eye do 
not modify the degree of astigmatism. The curvature of the 
corneal meridians remains the same during active accommoda- 
tion and during the passive state. 

In many respects the most admirable test of astigmatism is by 
the method of retinoscopy. This is explained on page 133. 

Correction of Astigmatism. — There are several methods 
by which we may proceed to measure astigmatism. Astigmatism 
may exist in a very low degree, associated with a much higher 
degree of hypermetropia or myopia, or a marked astigmatism 
may exist alone, or with ametropia of the other meridians, 



170 DISEASES OF THE EYE. 

or finally mixed astigmatism may be present. Each of these 
conditions requires a separate method of procedure. 

1. In all cases of hypermetropia or myopia, after the highest 
visual acuity has been developed with spherical lenses, and even 
if the radiating lines on the dial appear equally distinct, a weak 
convex and a weak concave cylindrical lens should be alternately 
placed in the trial frame, in addition to the spherical lens, and 
their axes rotated through 180°. 

If, by this manoeuvre, vision is improved and the patient 
enabled to read another line of the test letters, astigmatism is 
present. For example, if the vision of a case of hypermetropia 
of 3 D is improved by a convex 0.50 D cylinder, with its axis 
vertical, the glass required is + 3 D sph. 3 + 0.50 cyl., axis 
90° or vertical ; but if in the same case the maximum vision pre- 
viously obtained by + 3 D sph. is not improved by the addition 
of a convex cylindrical lens, a concave cylindrical lens is rotated 
throughout its axis until, if possible, the vision is increased. 
Suppose a concave cylinder of 0.50 D, with its axis at 180°, is 
found to improve vision or 4- 3 D sph. 3 — -50 D cyl., axis 
180°. This result is expressed in a simpler form by + 2.50 
D sph. C + -50 D cyl., axis 90°. (See page 40.) 

From this it is evident that any sphero-cylindrical combina- 
tion, where the spherical is designated by a plus ( + ), and the 
cylinder by a minus ( — ) sign, unless the cylinder is stronger 
than the spherical, can be reduced to a simpler form, obtained 
by subtracting the value of the cylinder from that of the spheri- 
cal ; the difference is the strength of the required spherical lens. 
A cylinder of the same strength as the one first employed, with 
its sign changed to correspond to that of the spherical, and the 
axis reversed, completes the process. This method of correct- 
ing astigmatism is best adapted to those cases in which the de- 
gree is 0.50 D or less. 

2. The position of the principal meridians is determined by 
means of the clock face, or Snellen's dial. (Fig. 71.) 

The most distinct lines correspond to the most ametropic meri- 
dian ; therefore, a stenopaic slit is inserted in the trial frame, in 
a direction at right angles to this. If vision is normal in this 
direction, the meridian must be emmetropic and the astigmatism 



NORMAL AM' ABNORMAL REFRACTION. 



171 



is simple. The slit is then turned at right angles to it- previous 
direction, and the glass found which gives the highest vision. 



Fig. 71. 




Wallace's astigmatic chart reduced to one-sixth of its diameter. 

The astigmatism is represented by this glass. The following 
are examples : — 

S nple Hypermetropic Astigmatism.— The patient sees horizontal lines 
most distinctly ; the stenopaic slit is placed vertically in front of the 

eye : and through thisF=— ; with the stenopaic slit horizontally placed, 

V = „-, with +1D added, V= ; hence +1D cyl., axis 90°, is 

the glass required. 

SimpU Myopic Astigmatism. — The patient sees vertical lines most 

distinctly ; the slit is placed horizontally : V = — ; with the slit placed 

vertically : V = -^- ; with — 1.50 added, V = a ; hence — 1.50 cyl., 
axis 180-, is the glass required. 

3. The patient may Dot perceive any difference in the distinct- 
ness of the radiating lines until a spherical lens is placed in front 



172 DISEASES OF THE EYE. 

of the eye, when some of them become more distinct than the 
others. The slit is now introduced in a direction at right angles 
to the distinct lines. Vision is not normal, but a spherical lens 
improves it, and that lens which gives the best vision with the slit 
in this direction is selected. The slit is then reversed. The visual 
acuity is less through the slit in this position than in the previous 
one, and a higher lens is necessary to secure the best vision. The 
astigmatism is represented by the difference between the stronger 
and weaker lens. This is an example of compound astigmatism, 
and is corrected by a spherical lens of the same strength as that 
which neutralizes the least ametropic meridian, and a cylindrical 
lens equal to the difference between the two meridians. The fol- 
lowing are examples : — 

Compound Hypermetropic Astigmatism. — No lines appear distinct, or 
perhaps the horizontal ones only slightly, so, but a convex glass makes 
the horizontal lines decidedly more distinct than the others. The slit 

is introduced in a vertical direction : V= -^ ; with + 1.50 spherical 

added, V = . The slit is now turned into a horizontal direction : 
6 

c c 

V=-^ - : with + 3.50 D. sph. added, V= — . The glass required for 

such a case is -f- 1.50 D. sph. 3 + 2 D. cyl., axis 90°. 

Compound Myopic Astigmatism. — No lines are distinct, but a concave 
spherical possibly makes the vertical lines more distinct, than the others, 
if the visual acuity is not too much lowered. The slit is introduced in 

the horizontal direction : F = ,- ; with — 5 D added, V = —. The slit 

60 12 

is now placed vertically : V — ~ , — 7 D is added, and V rises to „.,. 
1 J 60 12 

The glass required is — 5 D sph. 3 — 2D cyl. , axis 180°. 

All that has been said pertaining to the selection of glasses in 
myopia applies equally here. It is often impossible to correct 
the astigmatism by this method, and recourse must be had to tin 1 
first method by developing the best possible vision with spherical 
lenses, and then adding cylinders to still further elevate the visual 
acuity. 

Mixed Astigmatism. — Hypermetropia exists in one principal 
meridian, and myopia in the other. Usually no set of lines 
appears plainer than the rest, but the addition of a concave or 



NORMAL AND ABNORMAL REFRACTION. 173 

convex spherical brings out some lines more distinctly than the 
others. Thus a due to the principal meridians is obtained. 
With the slit before the eye, a convex spherical lens is placed 
in position and the slit rotated until the vision becomes more 
distinct. The hypermetropic meridian has then been found. 

JExamph : Suppose the hypermetropic meridian to be horizontal, and 
V to be most improved by -+- 3 D. The slit is turned to the vertical 
position, and it is found that a — 4 D gives the best vision. The differ- 
ence between these two meridians is 7 D. A -+- 7 cylinder, axis 90°, 
placed before such an eye would produce a myopia of 4 D, while a — 7 
cylinder, axis 180°, would produce a hypermetropia of 3 D, conse- 
quently with the -f- 7 cylinder, we must associate a — 4 spherical, and 
with the — 7 D cylinder, a -+- 3 D spherical. Such a case could be 
corrected by either of the following formulas : +3D sph. O — 7 
D cyl., axis 180° ; or — 4 D sph. C + 7 D cyl., axis 90 ; or by means 
of two cylindrical lenses with their axes at right angles to each other, 
viz., + 3 D cyl., axis 90° C — 4 D cyl., axis 180°. 

The spherical lenses may be weakened to meet requirements of 
the accommodation, but it may be accepted as a broad rule, with 
few exceptions, that the astigmatism is to be fully corrected if 
the degree can be definitely determined. 

After the correction has been determined by any one of these 
methods, trial by one of the other plans should be made, in the 
hope of still further improving vision, because the highest visual 
acuity is always to be regarded as the best evidence of the accu- 
racy of the glass. When the correct glass has nearly been 
reached, the final selection is made by comparing the vision 
through this lens with the next weaker and the next stronger 
number, always deciding in favor of the weaker cylinder, unless 
the vision is distinctly improved by the stronger glass. 

The following additional facts concerning lenses require men- 
tion : If a sphere-cylinder is in position before an eye, and vision 
is improved by placing before it another cylinder of the same sign 
(+ or — ), with its axis at right angles to that of the first, it 
shows that a stronger spherical and weaker cylinder are required. 

If vision is improved by placing in position another cylinder 
of the same sign, with its axis parallel to the first, it shows that 
the same spherical with a stronger cylinder should be adopted. 

If vision is improved by placing in position another cylinder 



174 DISEASES OF THE EYE. 

of different sign, with its axis parallel to the first, it shows that 
a weaker cylinder with the same spherical is needed. 

If vision is improved by placing in position a cylinder of 
different sign, with its axis at right angles to the first, it shows 
that a weaker spherical with a stronger cylinder must be employed. 

Ordering of Glasses. — Glasses are ordered for astigmatic 
eyes under the general rules which govern the selection of glasses 
in hypermetropia and myopia. For distance, the full correction 
is ordered in myopic astigmatism and in mixed astigmatism ; 
in hypermetropic astigmatism, the spherical lens is sometimes 
weakened. In myopic astigmatism, the spherical lens is weakened 
for near work. Simple myopic and mixed astigmatism give an 
opportunity for simplifying reading glasses. This will be men- 
tioned under Presbyopia. 

Irregular Astigmatism. — A low degree of this defect exists 
in nearly all eyes, but it does not interfere with good vision. 
AVhen its degree is increased by irregularities of the corneal sur- 
face from ulcers and cicatrices, the vision is very much reduced. 
Sometimes one meridian of regular curvature can be found, and 
by means of a cylindrical lens vision can be improved Stenopaic 
spectacles render vision more distinct, but they embarrass the 
wearer by limiting the field of vision. An iridectomy some- 
times improves vision very much by displacing the pupil towards 
a more regular portion of the cornea. 

Anisometropia. — This term includes cases in which one 
eye is much more hypermetropic or myopic than its fellow, or 
when myopia exists in one eye and hypermetropia in the other. 
Sometimes both eyes cannot be fully corrected because of the un- 
equal or opposite prismatic effects caused by looking through 
such lenses near their margins. This produces diplopia, or strain 
on the ocular muscles. Sometimes the decision must rest on 
the sensations of the patient, but frequently the best result is 
obtained when both eyes are corrected. If discomfort ensues, 
success may follow the attempt to train the function of the more 
defective eye by temporarily excluding the other from vision. 

Presbyopia. — The accommodation diminishes gradually from 
early life onward, and the near point recedes farther from the eye 
with each succeeding year. As long as it remains within 20 or 



NORMAL AM' ABNORMAL REFRACTION. 175 

30 cm., ii" appreciable inconvenience in reading is noticed ; but 

when the near point has fallen off to a greater distance than this, 
it is not possible to read fine type without the aid of convex 
glasses, mile— the visual acuity is much above the average, or 
the pupils unusually small. This condition is termed presbyopia, 

and is a normal result of growing old. 

Causes. — The cause of presbyopia consists in hardening of 
the crystalline lens, which is thus prevented from assuming 
the increased convexity which constitutes the essential factor of 
accommodation. 

This increase of convexity, necessary for seeing near objects, 
must be supplied to the eye by a spectacle lens. In the first 
stages of presbyopia, while considerable accommodation still re- 
mains, a weak convex lens is required, which enables the person 
to see near objects by rendering the rays less divergent, as if they 
came from a somewhat greater distance. 

When the accommodation is entirely obliterated at 75 years of 
age, the convex glass must be stronger. The rays are now ren- 
dered parallel, as if they came from an infinite distance. In 
order to produce this, the object must be held at the focus of the 
lens. There is, therefore, no range of vision. 

In the earlier stages there is still a range of vision from the 
focal distance of the glass to the near point. A person who has 
an accommodation of 3 dioptres, and requires + 1.50 D in ad- 
dition, will have a range from the focal distance of the glass 

1 metre 

. == 66 cm. to his near point through the glass ; 3D + 

1.50 

1.50 D = 4.50 D : 1 meter = 22 cm. 
' 4.50 

Patients occasionally postpone the time of wearing reading 
glasses, by holding fine objects in a bright light, the resulting 
contraction of the pupils rendering vision more distinct. 

Presbyopia usually begins at the age of 45. Unusual visual 
acuity, or vigor of accommodation, however, enables a person 
to dispense with glasses for several years longer. A visual 

acuity of — enables its possessor to see the same object distinctly 
4 

n 

at 30 cm. which another individual with an acuity of only — would 

6 



]76 DISEASES OF THE EYE. 

have to hold at 20 cm. Presbyopia is to be distinguished from 
hypermetropia, which is often latent and confounded with it. 
Correction of hypermetropia restores the far point of the eye to 
infinity. 

Correction of Presbyopia. — The correction of presbyopia 
is determined after the eye has been rendered emmetropic by 
neutralizing any hypermetropia which may exist. Presbyopic 
correction brings the near point closer, but it also diminishes the 
distance of the far point. 

It is necessary to observe caution that unduly strong glasses 
are not employed in approximating the near point, lest the far 
point be brought too close and serious discomfort ensue. Most 
people read at an average distance of from 30 to 40 centimetres. 
In early presbyopia, considerable range of vision exists on either 
side of these points ; but at 60 years and later there is little play, 
and the near point and far point are very close together. Unless 
there is diminished visual acuity, at this age the glass should be 
given with which the patient reads best at a distance of 30 to 40 
centimetres. 

The refraction of the eye should be rendered normal by cor- 
recting all hypermetropia and astigmatism. The management of 
myopia under these circumstances will be elsewhere considered. 

The near point of vision should be carefully determined for 
each eye separately. The ability to read 1 -metre type at 30 cm. 
is not equivalent to the act of accommodating for 30 cm.; in 
order fairly to accommodate for 30 cm. the patient should be 
able to read type which represents normal vision at 30 cm. (See 
page 47.) If the accommodation is normal, the near point will 
correspond closely with the figures given in the table. The 
additional refractive power required may then be calculated. 

Table of the position of near point at different ages. 

Age. Accommodation. P. 

45 . . . . 3.50 dioptres .... 29 cm. 

50 . . . . 2.50 " .... 40 " 

55 . . . . 1.75 " .... 57 " 

60 .... 1 " .... 100 " 

65 50 " .... 200 " 

70 25 " .... 400 " 

75 00 . . . . oo 



NORMAL AND ABNORMAL REFRACTION. 177 

At the age of 45 it is usually necessary to supply a 4- 1 dioptre 
spherical lens for reading, provided the eye is emmetropic j if the 
eye is hypermetropic, 1 dioptre ■+- the correction for the hyper- 
metropia; if myopia exists, + 1 dioptre is not required. Plus 1 
dioptre added to the 3.50 dioptres of accommodation which the 
eye possesses at 45 years = 4.50 D; this brings p to 22 cm. 

(±9®.= 22V and rto 100 cm. 
\4.50 /' 

At 50 years of age + 2 dioptres are usually required, with the 
same modifications in case of hypermetropia or myopia. This 
glass, added to the accommodation which the eye possesses at 50, 
viz., 2.50 dioptres, also makes 4.50 D; this brings p to 22 cm., 
but /• is now only 50 cm. distant. 

At bo years, -+- 2.50 D is the glass usually required, which, 
added to the accommodation (1.75), gives a refractive power of 
4.25 D; j) = 23.5 cm., r = 40 cm. If stronger lenses than 
this are used, r is brought still closer, and the patient is forced 

to hold his book near the face. So long as V= — , it is not 

necessary to order auy stronger glass than this. Sometimes 4- 3 
may be more satisfactory and may be ordered, but most people 
prefer a glass which enables them to read, resting the book on 
the lap or the arm of a chair. It is once more reiterated that 
these glasses are for emmetropic eyes. In hypermetropia with 
presbyopia, they are to be added to the hypermetropic correction. 

As visual acuity diminishes, a stronger lens is necessary to en- 
able the object to be held closer, and thus subtend a larger visual 
angle. The glass may be increased to 4, 5, 6, or even 8 dioptres. 
The strong glasses necessitate the close approximation of the ob- 
ject and a corresponding diminution in the field of vision. The 
only rule in the selection of such glasses is to give that glass 
which affords the necessary vision with the least inconvenience. 
With very great diminution of sight, requiring glasses of 8 or 10 
dioptres, binocular vision is impossible, and the better eye should 
be supplied with a correcting glass, and the other excluded from 
vision. 

With binocular vision, the reading glasses for the two eyes 
should be equal in strength ; consequently, when a different 
12 



178 DISEASES OF THE EYE. 

degree of ametropia exists in the two eyes, a corresponding differ- 
ence should be made in the reading glasses. 

Sometimes modifications are required in the strength of the 
glass, to suit particular vocations ; for example, reading music, 
working at a bench, etc. Under these circumstances, it is neces- 
sary to ascertain the distance from the eye at which the work is 
placed, and to order a glass, whose focal distance is not less, but, 
if possible, somewhat greater than the distance required. 

In myopia, myopic astigmatism, and mixed astigmatism, the 
rules for the selection of reading glasses call for particular men- 
tion. Patients with low degrees of myopia, not higher than 2 I>, 
do not require reading glasses at as early an age as emmetropic 
or hypermetropic subjects. 

The amount of myopia may be considered the equivalent of 
the convex glass suitable for the correction of the presbyopia. 
A myopia of 1 D, consequently, would enable a person to attain 
the age of 50 without the necessity of reading glasses. At that 
age he would require + 1 D for reading, and at 55 4- 1.50 I >. 
and at 60, possibly 4- 2 D, depending upon his visual acuity. 
A myope of 2 D could dispense with reading glasses until the 
age of 55 (often until a later period) ; then he would require 
+ .50 D ; at 60, possibly + ID. A myope of 3 or 4 dioptres 
never becomes presbyopic in the ordinary sense ; he can read at 
anv age without glasses. In early life he may wear his correo 
tion for distance and reading ; later on it is 1 tetter for him to read 
without glasses. 

In higher degrees of myopia, it is necessary to order a concave 
glass from 2 to 5 dioptres less than the full correction. The age 
has little influence on the amount of reduction; myopes practi- 
cally do not accommodate; the degree of myopia and the visual 
acuity are the two important factors. A concave glass is given 
which will extend the far point to a comfortable distance. A 
myope of 6 dioptres would probably require from — 3 to — 4 
dioptres for reading : a myope of 10 D, about — 6 dioptres, and 
a myope of 15 or 20 dioptres would require a reduction of 5 or 
6 D from the full correction. In these high grades. 1' is much 
reduced, print cannot be seen unless held close to the eye, so that 
extension of the reading distance is out of the question. The 



NORMAL AND ABNORMAL REFRACTION. 170 

farthest point at which a book can be read should be deter- 
mined, and a glass given of the same length of focus. Prisms 
arc often oecessary. When the vision is much reduced, myopes 
will sometimes read best with one eye without the aid of any 
glass. 

A patient with simple myopic astigmatism usually reads best 
with a convex cylinder <»f the same number, its axis being re- 
versed. Thus, a patient whose myopic astigmatism is corrected 
by —2D cyl., axis 180°, will be comfortable with a + 2 I) cyl., 
axis 90°. This glass with the myopic astigmatism produces a 
myopia of 2 dioptres in all meridians, and because the patient has 
been accustomed to see through a myopic meridian, he prefers this 
glass to the concave cylinder which makes him accommodate. As 
a rule, simple myopic astigmatism may be utilized to determine 
the reading glass in patients who have reached the age of 35, pro- 
vided its degree is not too high. A CQnvex cylinder, of a strength 
equal to the concave cylinder, with its axis reversed, will be 
sufficient. 

If the degree of myopia thus produced is too great for com- 
fortable reading, a concave spherical lens may be added to the 
convex cylinder. Thus, an astigmatic eye corrected by a — 4 D 
cyl., axis 180°, would probably require — 1.50 D sph. 3 + 4 
I) cyl., axis 90°. 

If the degree of astigmatism is unequal in the two eyes, a 
spherical lens is required over one eye to equalize the refraction. 

For example : (1) R. E. — 5 D cyl., axis 180°. L. E. — 3 
D cyl., axis 180°. This case requires a — 2 spherical to be 
added to the right eye, viz., — 2D sph. ^ + 5 D cyl., axis 
90°, to make its refractive power equal to that of the left, 3 
I) cyl., axis 90°. 

(2) R. E. — 1 D cyl., axis 180°, L. E. — 2.50 D cyl.. axis 
180°. In this instance, according to the circumstances, age, etc., 
one of the following combinations may be ordered : R. E. +1 
I) cyl., axis 90°, L. E. — 1.50 D sph. 3 + 2.50 D cyl., axis 
90°; or R. E. + 1.50 D sph. C +1D cyl., axis 90^, L. E. 
+ 2.50 D cyl., axis 90°. Both of these combinations equalize 
the refraction of the two eyes, the first by producing in each eye 
a myopia of 1 dioptre, the second a myopia of 2.50 dioptres. 



180 DISEASES OE THE EYE. 

When, in cases of compound myopic astigmatism, the myopia 
amounts to several dioptres, the reading glass is secured by a suffi- 
cient reduction of the strength of the spherical without change 
of the cylindrical lens. 

When, in lower degrees of compound myopic astigmatism, it 
is desirable to increase the refraction one or more dioptres, the 
procedure is somewhat different. Thus, if the combination is 

— 0.50 D sph. 3 — ID cyl., axis 180°, and the spherical lens is 
omitted, + 0.50 dioptre is gained ; by substituting for the concave 
cylinder a convex cylinder with its axis reversed, an additional 
gain of 1 dioptre is secured ; + 1 D cyl., axis 90°, in this case is 
equivalent to adding 4- 1.50 I) sph. to the original combination. 
If still more refractive power is desirable, e. g., + 2 D, 4- .50 
D sph. ^ +1D cyl., axis 90°, gives the additional amount. 

In another combination, — .75 D sph. ^ — 4 D cyl., axis 1 80°, 
it is desired to add + 2.50 D for reading. Dropping the 

— 0.75 D spherical, 4- 0.75 D of refractive power is obtained ; 
substituting for the concave cylinder, convex 4 D cyl., axis 90°, 
4- 4 D more are gained, making 4- 4.75 D. This is too high, 
hence it would be necessary to combine — 2.25 D sph. 3 + ^ 
D cyl., axis 90°, in order to obtain the desired 4- 2.50 D. A 
simpler method of procedure in this case would be to drop the 

— .75 D spherical ; the uncorrected myopia would then furnish 
.75 D of the requisite 2.50 D, leaving 1.75 to be obtained. A 
4- 1.75 D added to the — 4 D cyl., axis 180°, would make the 
proper combination. 

In mixed astigmatism, a combination of spherical lens and 
cylinder is usually employed, and by using a concave spherical 
and convex cylinder we can easily find the combination neces- 
sary to produce any additional refractive power. 

If the myopia produced by the convex cylinder alone is greater 
than the power of the lens it is desired to add, a concave spherical 
equal to the difference is given, thus: To the combination — 3 
D sph. 3 4- 5 D cyl., axis 90°, it is desirable to add 4- 2 D. 

— 34- 2 = — 1, hence — 1 D sph. 3+5D cyl., axis 90°, 
is the glass required. Again, to — 1 D spin 3 + 3 D cyl., axis 
90°, it is desirable to add + 2.50 D. — 1 ^f 2.50 — 4- 1.50, 



NORMAL AND ABNORMAL REFRACTION. 181 

hence 4- 1.50 D sph. 3 + ■' D cyl., axis 90°, is the necessary 
glass. The myopia is in this case insufficient. 

It is a point of some importance, in ordering reading glasses 
containing cylindrical lenses, to give attention to the relation of 
the axes of the cylindrical lenses. It has been assumed, for the 
sake of simplicity, that the axes of convex cylinders are placed 
at 90° and the axes of concave cylinders at 180°; this is com- 
monly so, but the exceptions are numerous. It is a frequent 
condition in astigmatism to have one principal meridian inclined 
15° to the right of the vertical in one eye, while the meridian of 
the same refraction in the other eye is inclined the same amount 
to the left of the vertical. This produces no serious disturbance 
in wearing the glasses if they are properly centred, although at 
first a rectangular figure appears like a rhombus. In a little 
time the eyes adapt themselves to the glasses, and this appearance 
is lost. 

When the meridians of similar refraction are at greater angles 
than this, especially if the cylindrical lenses are strong, there is 
often inconvenience in wearing them on account of the prismatic 
deviation and the unequal distortion of objects which cylindrical 
lenses produce. Occasionally the axes are as much as 90° apart, 
one at 45° and the other at 135°, or one at 90° and the other 
at 180°. The glasses now deviate rays from an object in dif- 
ferent directions, according as the eye looks through the glasses 
above or below the optical centres, or to the right or left of 
them. Such a case would be represented by +3D cyl., axis 
180°, in right eye, and -f 3 D cyl., axis 90°, in left eye. The 
difficulty is not obviated by ordering a formula like the follow- 
ing : R. + 3 D cyl., axis 180°, L.+3D sph. 3 — 3 D cyl., axis 
180°, because the same displacement results. It will be found 
that the best solution of this difficulty is to ascertain the distance 
from the eye at which the person usually holds the book, and the 
relative position it occupies to the eye. The direction of the 
visual lines may thus be determined, and the optical centres of 
the glasses should be so placed that the visual lines will pass 
through them. There is then no deviation. Of course this 
renders necessary a separate pair of glasses for reading. When 
cylindrical lenses with axes in unusual directions are required 



182 DISEASES OF THE EYE. 

for distance, the optical centres should bear the same relation to 
the visual lines in distant fixation. These disturbances are aggra- 
vated by removing the glass farther from the eye, and conversely 
the trouble diminishes as the glass is brought nearer to the eye. 1 

SPECTACLES AND THEIR ADJUSTMENT. 

After the refraction of the eye has been determined and the 
proper combination of lenses selected, the glasses should be 
properly ground, mounted in spectacle frames, and correctly 
adjusted to the patient's eyes. Patients should not be allowed 
to wear glasses until the surgeon has satisfied himself that the 
formula for the lenses has been faithfully followed by the manu- 
facturing optician. 

In order to do this, he proceeds as follows : If a simple spheri- 
cal lens has been ordered, this and a spherical leus from the trial 
case, of the same number but opposite refractive character, are 
placed in close contact and some distant object observed through 
the combination, while the glasses at the same time are gently 
shaken up and down, and moved to and fro. If the glass is 
correct, this manoeuvre has no influence upon the size or position 
of the object, which appears exactly as it would if it had been 
looked at through a piece of plane glass. The glasses are then 
said to neutralize each other. If the lens ordered does not 
neutralize the test-glass from the trial box, a weaker or stronger 
number is tried until the glass is found which produces complete 
or nearly complete neutralization. Thick bispherical lenses of 
different refractive character will not neutralize each other en- 
tirely even if they are of the same number. The convex lens 
always preponderates. With a suitable " lens-measure " the char- 
acter of a lens can be quickly determined. 

If a cylindrical lens has been ordered and has been correctly 
ground, it will be neutralized by a cylinder of the same number 
but of opposite refraction with its axis turned to the same angle 

'Consult interesting papers in the Archives of Ophthalmology, Vol. xviii., by 
Dr. J. A. Lippincotl ; in the < Ophthalmic Record, Vol. i., No. 1, by Dr. G. C. Savage; 
and Dr. R. J. Phillips in the Annals of Ophthalmology, Vol. ii., p. 31. 



NORMAL AM> A.BNORMAL REFRACTION. 183 

as that of tli<' lens ordered. ( >n shaking these two lenses, which 
arc phucd in contact, there should be no motion of the object 
viewed through them. The direction of the axis of a cylinder 

may be determined by finding the position in which the lens 
may be shaken without producing any motion of the object. 
For example, if the axis of the cylinder is vertical, no motion 
in the object looked at would occur when the spectacle lens is 
moved up and down. A line drawn on the glass with a pen 
marks this, and by placing the lens thus marked on a "protractor 
the degree of the angle may be read off. A convenient object 
for thus testing a cylinder is the sharp edge of a door. To deter- 
mine the strength of a cylindrical lens it simply is necessary to 
rind the spherical or cylindrical lens which neutralizes the mo- 
tion of the edge of a door viewed through the cylinder when 
this is shaken at right angles to its axis. The axis of the cvl- 
inder should be held parallel to the edge of the door and the 
glass moved in a horizontal direction. 

A combination of spherical and cylindrical lenses is to be tested 
by a spherical lens held on the spherical surface of the spectacle 
lens, and a cylindrical lens held at the cylindrical surface of the 
spectacle lens, proceeding in the manner just described. 

The optical centre is now to be determined, and this can be 
il< »ne by reflection. For example, the surgeon stands with his back 
to a window, and rinds the point on the lens where the image of 
the window-bars from the anterior surface, and the image from 
the posterior surface, overlie each other; the optic axis must unite 
these two points, and the optical centre is on this line. 

A simpler method is to fiud two meridians of the lens at right 
angles to each other through which a vertical liue is not dis- 
placed horizontally, as each meridian is brought parallel with the 
vertical line. The intersection of these meridians is the pole or 
summit of the lens ; the axis of the lens passes through this point, 
and the optical centre is on this axis between the two surfaces. 
If the lens is a cylinder or sphero-cylinder, the two meridians 
must be chosen, which are respectively parallel and at right 
angles to the axis of the cylinder. The examiner proceeds as 
follows : The lens is held by the edges between the finger and 
thumb, and, care being taken not to hold it oblicpuely, it is 



184 DISEASES OF THE EYE. 

passed from right to left until the test object (edge of a door or 
vertical line) forms a continuous line above the lens, through 
the lens, and below the lens. If the axis of the lens is not ex- 
actly in line with the edge of the door, the part seen above and 
below the lens will not coincide with the part seen through the 
lens. When a continuous line is obtained through the lens with 
the object above and below, the lens should be marked with a 
line drawn across its surface over the part where the edge of the 
door or wall is seen, just as the outline of a figure is traced on a 
transparent plate. The glass is now turned around so that the 
line is at night angles to its former position ; another portion of the 
lens is found through which the edge of a door is also seen in a 
continuous line with the part above and below. This is traced on 
the glass with ink, and the intersection of the two lines thus 
traced marks one extremity of the axis of the lens. In most lenses 
the distance from the surface to the centre is so slight that we 
may consider this point on the surface as the centre, and each lens 
should have its centre marked by a dot of ink. Strong lenses may 
be centred more easily, by using the window-bars, while the glass 
is held close to them, or the edge of a card or sheet of paper, 
which is laid on the desk. Still greater accuracy may be ob- 
tained by using a card, on which two lines are drawn, crossing 
each other at right angles ; both principal meridians may in this 
way be found at once; the optical centre then lies over the inter- 
section of the lines. 

The spectacles should now be placed on the patient, and the 
position of these centres in relation to the pupil carefully noted. 
The patient is first asked to look across the room ; the centres of 
the pupils should correspond with the dots on the glasses. Next, 
the patient is required to look at the finger of the surgeon held 
at 40 cm. distance, and it will be noticed that the centres of the 
pupils and the dots no longer coincide, but that the former have 
passed to the inner side of the latter. If the glasses are for dis- 
tance or for constant wear, the space between the centres of 
the lenses should be the same as the inter-pupillary distance; 
if the glasses are for reading alone, the distance between the 
centres must be lessened. The ordinary reading distance being 
40 cm., the visual lines converge to this point, and the farther 



NORMAL AND ABNORMAL REFRACTION. 185 

the glasses are from the centre of rotation, the nearer the centres 
Bhould come to each other; therefore, it is necessary to make the 
distance between the centre- of the reading glasses from 2 to 4 
mm. less as compared with those of distance glasses, so that the 
visual lines may pass through these centres. Thus: The centre 
of the pupil deviate- inwards about 1 mm. in fixing at a point 
40 cm. distant, as the pupil is 11 mm. in front of the centre of 
rotation ; a glass placed 13 mm. in front of this would require its 
optical centre to be 1 mm. farther inwards than the pupil; 2 mm. 
in all. The two centres should thus be 4 mm. nearer together in 
reading glasses than in those for distance. 

When glasses are ground with badly placed centres — that is, too 
far apart or too close together — the most unpleasant consequences 
may arise : obstinate diplopia, severe neuralgia, headache, and 
tendency to squint. Patients are often unable to wear a correc- 
tion, which otherwise would afford the greatest benefit, because 
the lenses are centred so badly that the straight muscles of the 
eye are kept on a strain in order to relieve the diplopia which 
the prismatic effect of the lenses produces. 

The inter-pupillary distance should be carefully measured to 
determine what the distance should be between the centres of 
the glasses. It is difficult to find the centre of a dilated pupil, 
and hence the margin of the iris on the right side of each pupil 
may be selected. The patient should observe some distant object 
while the inter-pupillary distance is measured during distant fix- 
ation, and then fix his eyes on the finger-tip of the observer, 
held about 30 cm. from his eyes while the measurement is noted 
during convergence. There should be a variation of 2 mm. be- 
tween these two measurements. If the difference is greater than 
this, there is a probability that the patient has an insufficiency of 
convergence, and, in this case, the centres of convex glasses should 
be brought closer together ; those of concave glasses placed farther 
apart. 

In order to ascertain the amount of deviation which is pro- 
duced by decentering a spherical lens, the following tables, 
which have been prepared by Dr. Edward Jackson, will be 
found useful, together with the descriptions of the tables taken 
from Dr. Jackson's paper. 



18G 



DISEASES OF THE EYE. 



In Table I., the first column gives in dioptres the strength of 
the lens to be used. At the head of each of the other columns 
is given the prismatic deviation required. The method of ob- 
taining this is pointed out below; the columns give the respective 
distances in millimetres that the optical centres must be removed 
from the visual axis to produce such an effect. 



Table I. — Decentering required to produce a given deviation. 



0.5° d. l°d. 



DEVIATION REQUIRED. 

1.5° d. 2°d. 2.5° d. 



3°d. 



4° d. 5° d. 



Lens 

1 D 

2 " 

3 " 

4 " 

5 " 

6 " 

7 " 

8 " 

9 " 
10 " 



In Table II., the first column gives, as before, the strength ot 
the lens ; the head of each of the other columns shows the refract- 
ing angle of the prism equivalent to the amount of decentering 
indicated by the figures beneath, which indicate in millimetres the 
distance the optical centre is to be removed from the visual axis. 

Table II. — Decentering equivalent to a given refracting angle 
{index of refraction, 1.54). 





AMOUNT 


OF DECENTERING 


NECESSARY. 






8.7 


17.5 


20.2 


34.9 


43.6 


52.4 


69.9 


B7.5 


4.3 


8.7 


13.1 


17.5 


21.8 


26.2 


34.9 


43.7 


2.9 


5.8 


8.7 


11.6 


14.5 


17.5 


23.3 


29.2 


2.2 


4.4 


6.5 


8.7 


10.9 


13.1 


17.5 


21.9 


1.7 


3.5 


5.2 


7 


8.7 


10.5 


14 


17.5 


1.5 


2.9 


4.4 


5.8 


7.3 


8.7 


11.6 


14.6 


1.3 


2.5 


3.7 


5 


6.2 


7.5 


10 


12.5 


1.1 


2.2 


3.3 


4.4 


5.4 


6.5 


8.7 


10.9 


.9 


1.9 


2.9 


3.9 


4.8 


5.8 


7.8 


9.7 


.9 


1.7 


2.6 


3.5 


4.4 


5.2 


7 


8.7 













NO. OF PRISM. 








Lens ... 1 


2 


3 4 5 

DECENTERING REQUIRED. 


6 


8 


10 


ID. . . 9.4 


18.8 


28.3 37.7 47.2 


56.5 


75.8 


95.2 


2 " 






4.7 


9.4 


14.1 18.8 23.6 


28.2 


37.9 


47.6 


3 " 






3.1 


6.3 


9.4 12.6 15.7 


18.8 


25.3 


31.7 


4 " 






2.3 


4.7 


7.1 9.4 11.8 


14.1 


18.9 


23.8 


5 " 






1.9 


3.8 


5.7 7.5 9.4 


11.3 


15.2 


19 


6 " 






1.6 


3.1 


4.7 6.3 7.9 


9.4 


12.6 


15.9 


7 " 






1.3 


2.7 


4 5.4 6.7 


8.1 


10.8 


13.5 


8 " 






1.2 


2.3 


3.5 4.7 5.9 


7.1 


9.5 


11.9 


9 " 






1 


2.1 


3.1 4.2 5.2 


6.3 


8.4 


10.5 


10 " 






.9 


1.9 


2.8 3.8 4.7 


5.6 


7.6 


9.5 



NORMAL AND ABNORMAL REFRACTION. 187 

Reading glasses should be kilted forward and placed about 5 
nun. lower down than those for distance, in order to conform 
with the depression of the visual line in reading. Spectacles are 
always t<> be preferred, and in high grades of astigmatism they 
are essential ; but the prejudice of many patients in regard to 
spectacles will often have to be respected. When the astigma- 
tism is not of high grade, and the individual has a sufficiently 
prominent nose, eye-glasses can easily be retained in place; but 
the tilting forwards of the glasses nearly always diminishes the 
acuity of vision for distance. This tilting is rather an advan- 
tage in reading glasses, and in myopia the effect of this tilting is 
equivalent to a cylindrical lens with a horizontal axis. This 
fact accounts for the preference shown by some patients for a 
simple concave spherical uncombiued with a cylindrical lens, in 
spite of the existence of a slight degree of astigmatism. 

When separate glasses are required for distance and reading, 
it is often very inconvenient to make the change from one to the 
other. The two glasses may be combined in the same frame by 
making the lower half suitable for reading, and the upper half 
for distant vision. A better arrangement is to have two seg- 
ments of a suitable spherical lens, ground very thin and cemented 
on the lower portion of the distance glasses, as a means of 
reading and seeing distant objects through one pair of glasses. 
These are known as bifocal lenses. "Hook fronts" are very con- 
venient for making a rapid change from reading to distant vision, 
or " half-hook fronts " may be employed. 



188 DISEASES OF THE EYE. 



CHAPTER V. 

DISEASES OF THE EYELIDS. 

Congenital Anomalies. — Complete absence of the lids (able- 
pharia totalis), or their partial development (ablepharia partialis), 
is a rare anomaly. If the defect is of such a nature that the lids 
are wanting, and the orbit divested of any covering for the globe, 
the condition is designated lagopkthalmos, a name which also, 
and perhaps more properly, has been given to a contracted state 
of the eyelids preventing their closure, independent of any mus- 
cular paralysis. 

Cryptophthahnos is a condition in which neither eyelid nor 
conjunctival sac is present, but the exterior integument passes in 
front of, and buries an eye more or less developed. 

Cleft eyelid (coloboma palpebral) is a fissure, in appearance not 
unlike a hare-lip, which may be confined to the upper lid (its 
most common situation), but which also has been noted in the 
lower lids, and even in the upper and lower lids on each side. 
The centre of the cleft contains an intervening membranous 
portion, either movable or pressed against the cornea. 

Coloboma of the eyelids is most frequently associated with 
hare-lip ; rarely with other congenital anomalies in the eyeball. 
The deficiency may be remedied by a plastic operation. 

Symblepharon or a cohesion, either partial or complete, between 
the eyelid and the ball, and ankyloblepharon, or a union between 
the margins of the lids, are unusual congenital anomalies. Some- 
times only the middle portions of the lid-borders are attached ; it 
may be bv a filamentous band, or the outer angles of the lids 
adhere, and produce the defect known as blepharophimosis. 

Ectropion, or eversiou of the edges of the eyelids, is a rare 
condition usually accompanied by increased size of the eye- 
ball. Entropion, or inversion of the edges of the lids, which in 
slight degree is said to be normal before birth, has been found 



DISEASES OF THE EYELIDS. 189 

associated with distichiasis, or the development of supplementary 
incurved eyelashes. 

The operations which are employed to rectify these conditions 
when of pathological origin (see page 584) are also applicable 
here. 

Epicanthus is a striking congenital anomaly giving rise to an 
apparent convergent strabismus, owing to the passage of a fold of 
skin from the inner end of the brow to the side of the nose, cover- 
ing the internal eanthus, its free concave border stretching out- 
wards. Thus the caruncle, lachrymal punctum, and in aggravated 
forms, a considerable portion of the area of the lids, are hidden. 
Epicanthus generally is bilateral and is usually associated with 
ptosis (Fig. 74). The same condition in minor degrees is often 
seen in newborn children, and disappears with the subsequent 
development of the face and nose. 

The defect may be remedied by excising a portion of the re- 
dundant integument from the bridge of the nose, and stitching 
together the opposed surfaces. 

Congenital ptosis consists in a drooping of the upper lid over the 
eyeball. It may be single or double, but never amounts to com- 
plete closure. In one variety there is an actual redundancy of 
the lid tissue ; in the other, the lid is thin and the skin stretched, 
owing to imperfect development or absence of the levator pal- 
pebne (Figs. 73 and 74). 

This anomaly is often associated with other vices of conforma- 
tion, especially epicanthus, and with paralysis of the external 
ocular muscles. It may be corrected by one of the operations 
described on page 581. 

Erythema of Lids appears in the form of a hyperemia, more or 
less diffused, under the influence of heat (sun-burn), traumatism, 
and irritating poisons, or as symptomatic of a systemic disturb- 
ance. 

A passive hyperemia, in which the superficial veins of the 
lid- are dilated and the tissue red and slightly swollen, com- 
monly is the result of prolonged bandaging of the eye, and is 
seen in an active state associated with most of the inflammatory 
diseases of the cornea and conjunctiva. 



190 DISEASES OF THE EYE. 

Treatment. — This consists in removal of the cause and the 
application of a soothing lotion, lead water or extract of hama- 
melis. 

Erysipelas rarely attacks the eyelids as a primary affection, 
but spreads to them from the contiguous facial area. The chief 
danger of the affection in this region is its liability to infect 
the tissues of the orbit, producing compression of the central 
vessels of the retina, and consequent blindness. It may spread 
to the membranes of the brain and be fatal. The characteristic 
red, shining, and later brawny swelling, and the formation of 
cutaneous vesicles and small abscesses, are the symptoms which 
establish a diagnosis. 

The treatment, both local and general, demands the same pro- 
cedures which are applied to the disease when located elsewhere 
in the body. 

Abscess of the Lid [phlegmon) appears as localized, red ele- 
vation, while the entire lid is hypersemic and the conjunctiva 
injected, and often cedematous. There is much pain, headache, 
and fever. This affection is provoked by injury, exposure, and 
disease of the orbit, and sometimes arises without ascertainable 
cause, especially in debilitated people and children. 

Treatment. — Pointing should be favored by a carefully ad- 
justed poultice (one covering the entire eye should not be used). 
or hot, slightly carbolized fomentations. As soon as fluctuation 
is detected, or even earlier, a sharp knife may be thrust through 
the swelling, parallel to the muscle fibres, and the contents 
evacuated ; the cavity is to be kept clean with an antiseptic fluid. 

Furuncle of the Lid is a localized inflammation of the skin 
and subcutaneous tissue, presenting symptoms analogous to 
abscess, which goes on to the formation of a central slough or 
"core." The surrounding and overlying tissue may become 
gangrenous in subjects of poor nutrition. 

MaMgnant pustule, or specific anthrax, caused by the entrance 
of the bacillus anthracis, and malignant (edema, or a form of 
spreading gangrene, are affections rarely seen upon the eyelids. 
The former usually arises among people whose occupation brings 
them in contact with diseased animals or decayed animal matter j 



DISEASES OF THE EYELIDS. 191 

the latter may follow an injury, hut has also beeD described a* 
an idiopathic affection. 

Treatment. — According to the condition present, this should 
include incision, promotion df the separation of the sloughs by 
poultices, the use of the actual cautery to check the destructive 
tendency, and antiseptic lotions. 

Hordeolum or Stye is a small furuncle or boil in the margin 
of the lid, and consists of a localized, suppurating inflammation 
of the connective tissue, or of one of the glands at this point. This 
may remain as a tender, circumscribed swelling, which becomes 
invested with a yellow cap indicating suppuration, or it may cause 
considerable pain, with cedematous swelling of the entire lid and 
cheiuosis of the conjunctiva. Some people are subject to a mild 
type of styes which appear in the form of superficial pustules 
along the margin of the lid. A characteristic feature of horde- 
olum is its tendency to recur, and a single stye, or several at 
a time, may appear again and again for many weeks. Certain 
occupations, such as driving in the cold or dust, and the strain 
of uncorrected ametropia, predispose to this disorder. Frequent 
" attacks" of styes indicate derangement of health, and are 
especially associated with constipation and menstrual irregu- 
larities. Girls about the age of puberty are commonly affected. 

Treatment. — A stye sometimes may be aborted by the 
vigorous application of a hot boracic acid lotion, or an ointment 
of the red or yellow oxide of mercury ; the same end is obtained 
by painting the inflamed surface with collodion. In the event 
of failure, suppuration should be encouraged by repeated appli- 
cations of small compresses steeped in hot water, and an incision 
should be made on the earliest appearance of pus by a knife 
thrust deeply through the base of the swelling, parallel to the 
edge of the lid. 

Exanthematous Eruptions on the eyelid are found during 
the course of various of the eruptive fevers. The pustules of 
smallpox, if they appear upon the eyelids, form by preference at 
the commissures, and in connection with the follicles of the eve- 
lashes. The subsequent pitting from loss of tissue may cause 
considerable disfigurement. 

Sometimes a pustule declines to heal and forms a chronic post- 
variolous ulcer. Vaccine vesicles (vaccine blepharitis) may form on 



192 DISEASES OF THE EYE. 

the lid margins from accidental inoculation, e. g., with the finger- 
nail previously in contact with a vaccine-pox. The vesicles may 
develop into a severe ulcer. 

Eczema of the Lids, independently of that variety which is 
located upon the ciliary margin and which is one of the forms 
of blepharitis, may appear upon the general cutaneous surface 
of these structures, usually in association with its presence else- 
where on the face and scalp, and is seen in the erythematous, 
vesicular, and pustular varieties. 

Eczematous eruptions upon the lids are also associated with 
inflammations of the cornea and conjunctiva, and arise under the 
influence of prolonged bandaging. Atropine, when it produces 
conjunctivitis (see page 249), may cause an eczema of the lids 
and surrounding face. 

Treatment. — This depends upon the character of the erup 
tion. If this is vesicular, a useful application is a drying powder 
composed of starch, oxide of zinc, and camphor ; if crusts have 
formed, these should be removed with as little bleeding as possible 
and with the aid of an alkaline solution, maceration of the epi- 
dermis being avoided, and one of the following ointments em- 
ployed : Plain oxide of zinc, or equal parts of oxide of zinc and 
vaseline to which 20 grains of calomel have been added ; or sub- 
nitrate of bismuth in au ointment. Itching is relieved by the 
application of lotio nigra followed by zinc ointment. If the 
disease assumes a chronic type, some preparation of tar (pix 
liqwida or oil of cade) may be used. Good results follow the 
use of aristol ointment, both in subacute and chronic; cases. 

As constitutional remedies, quinine, iron, and strychnia arc 
recommended, and arsenic, if the type is chronic. Proper regu- 
lation of diet, an occasional saline laxative, and good hygiene 
are important measures. 

Herpes Zoster Ophthalmicus is an inflammatory disease] 
characterized by an eruption of vesicles, situated upon inflamed 
bases, over the area supplied by two of the three branches of the 
ophthalmic, or first division of the trigeminus, viz., the frontal 
through its supraorbital and supratrochlear branches, and more 
rarely the nasal nerve. 

Neuralgic pain, heat, and redness of the skin precede the 



DISEASES OF THE EYELIDS. 193 

vesicles, which, varying in size from a pin's head to a split pea, 
appear in distinct crops, or coalesce in irregular patches. At 
first they contain a clear yellow fluid, later becoming turbid, 
until at the end of a week or more they dry up, and the brown 
scabs drop off, leaving beneath decided and often disfiguring scars. 

The disease may be mistaken for erysipelas, from which it 
should be distinguished by the acute neuralgic pain, and the 
formation of the vesicles in the course of a given set of nerves. 

Serious involvement of the eye itself, by the formation of 
blebs upon the cornea, and by inflammation of the iris and 
ciliary body, is often associated with the disorder. More or less 
conjunctivitis is always present. The blebs on the cornea rup- 
ture and form ulcers, which leave permanent scars, and the iritis 
and cyclitis may eventuate in a destructive inflammation of the 
deeper coats of the eye (ophthalmitis). Atrophy of the optic 
nerves and paralysis of the oculo-motor have followed ophthal- 
mic herpes. 

Inflammation of the tissues of the eye is most apt to occur 
when the nasal branch is affected, and the vesicles extend to the 
tip of the nose, because from this branch, through the lenticular 
ganglion, arise the nerves supplying the iris, ciliary body, and 
choroid. This is not an invariable rule, and destructive disease 
of the eyeball may appear even when the nasal branch is not 
involved. A severe and most intractable neuralgia often re- 
mains after the subsidence of the eruption. 

Herpes zoster ophthalmicus is more frequently seen among 
elderly people of feeble nutrition than among adults and young 
children, but the latter may be attacked even in the absence of 
constitutional depression. 

Treatment. — The disease runs an acute course and tends to 
spontaneous recovery in two or three weeks. Locally, anodynes 
are useful — lead-water and laudanum, weak carbolic acid lotions, 
and preparations of belladonna. Severe pain must be mitigated 
by opiates, and morphia hypodermically, while the best constitu- 
tional remedies are full doses of quinine and iron, and later 
arsenic. The post-neuralgic pain may be relieved by croton 
chloral hydrate in doses of 5 to 1 grains every four hours, and 
by the use of a mild galvanic current. If conjunctivitis, kera- 
13 



194 DISEASES OF THE EYE. 

titis, iritis, or cyditis arises, this requires the treatment directed 
to the relief of such conditions, which is detailed in the special 
sections devoted to their consideration. 

Blepharitis is the term applied to the various grades of sub- 
acute and chronic inflammation of the border of the eyelid, which 
for clinical purposes may be gathered into two groups — non-ulcer- 
ative and ulcerative blepharitis. The former may be studied under 
several subdivisions : — 

(1) Hypercemia of the lid border (hyperaemia marginalis, vaso- 
motor blepharitis). — The margins of the lids have an unpleasant, 
slightly swollen, red appearance. Exposure to cold wind or any 
strain upon the accommodation causes a feeling of heat, followed 
by burning and lachrymation. The redness is caused by the 
passive congestion of the superficial bloodvessels, and the affec- 
tion is unattended by the presence of scales or crusts, or these 
are but sparingly present. 

(2) Simple blepharitis (seborrhoea of the lid border, blepharitis 
ciliaris, squamous blepharitis). — This variety depends upon an 
abnormal secretion of the sebaceous glands, and results in the 
formation of scales and crusts situated on the margin of the lids 
at the bases of the eyelashes, or adhering to them, and may 
appear either in a dry or a moist form. Removal of the hardened 
sebum exposes the skin, shining and red and occasionally abraded, 
a procedure associated with the loss of a few cilia. There is 
usually slight conjunctivitis. An accompanying seborrhoea of 
the eyebrows and scalp may be present ; both lids are invariably 
affected, and the patients complain of burning, inability to per- 
form close work, and some dread of light. 

Exposure to cold and dust, and the use of the eyes, quickly in- 
crease the congestion of the lids. If the disease is of long dura- 
tion, or is subject to frequent relapses, considerable thickening 
of the lid margins is evident, due to the inflammation surround- 
ing the glands in the skin and tarsus. 

The second, or ulcerative form of blepharitis appears in several 
grades of severity as a special localization of — 

Eczema "jkhi the lid border (blepharitis ciliaris, blepharitis 
ulcerosa, psorophthalmia, lippitudo ulcerosa, tinea tarsi, sycosis 
tarsi, ophthalmia tarsi, etc.). 



DISEASES OF THE EYELIDS. 195 

a. Superficial form (marginal eczema). — This resembles in gene- 
ral that variety which has been described as hyperemia of the 
ciliary margin, and causes the patient much annoyance through 
the possession of " weak eyes/' from frequent attacks of redness 
and soreness of the borders of the lids, associated with the forma- 
tion of crusts, small pustules and ulcers at the roots of the lashes, 
without, however, seriously interfering with their nutrition or 
growth. 

b. Solitary form (blepharo-adeuitis eiliaris, a name given by 
Arlt). — This is characterized by the appearance of a circum- 
scribed area of thickening and redness of the lid margin, upon 
which the cilia are matted together at their bases by the forma- 
tion of thick yellow crusts. A single tuft of this kind may be 
present, or several on one lid border ; the process is frequently 
unilateral, in this respect, being unlike the squamous forms 
which are bilateral. Removal of the crusts evacuates a few 
drops of thin pus from the surface of the ulcer which lies 
beneath, and the cilia, which usually come away with the scab, 
have swollen and thickened roots. Spots of eczema at the nares 
and in the hair of the scalp may be present at the same time, as 
well as disease of the lachrymal passages. 

c. Pustular form (blepharitis eiliaris ulcerosa). — This manifests 
itself as an eczema of lid margins, in its worst types involving the 
four ciliary borders. Thick yellow crusts, which mat the eye- 
lashes, form along the palpebral margins, covering deep ulcers 
which readily bleed, and, often crater-shaped, pass inward to the 
tarsus. 

The inflammatory process, if unchecked, seriously interferes 
with the nutrition of the lashes and the edges of the eyelid. 
The former become stunted, curled, misplaced (trichiasis), or drop 
out, and may be entirely wanting (madarosis, tylosis). The latter 
assume a rounded shape, are swollen, reddened, thickened, slightly 
everted, and deprived of cilia (lippitudo or " blear eye," hyper- 
trophic blepharitis), and if the punctum lachrymale is displaced or 
closed, an overflow of tears adds to the discomfort of the patient. 

It is not always possible thus sharply to separate the various 
types of blepharitis, as they often shade one into the other; 
nor is it always safe to decide between those which arise from 



196 DISEASES OF THE EYE. 

glandular hypersecretion and those which are due to eczema. 
After the cure of an ulcerative variety, small scales may form 
resembling the simple or squamous type, while the latter may 
also lead to, or be associated with, ulcerations. 

Etiology. — In the majority of instances blepharitis is a disease 
of childhood, and is common near the age of puberty ; the aggra- 
vated forms, especially those resulting in chronic changes in the 
ciliary margins, are frequently seen in adults as the result of 
neglect. The malady may follow in the wake of an exanthem, 
particularly measles, and finds many subjects among children of 
strumous habit, with blonde hair and pale complexion. The 
usual presence of considerable degrees of ametropia has led to 
the belief that this causes blepharitis (Roosa). There is no doubt 
that it aggravates and fosters the condition. 

Of considerable importance in the origin of this affection are 
inflammations of the tear-sac, stricture of the nasal duct, ami 
obstructive disease of the posterior nares, although it may be 
difficult in individual cases to decide whether the blepharitis 
has caused the closure of the lachrymal passages, or whether 
this has developed the blepharitis. Finally, some instances ap- 
pear to arise from an abnormal shortness of the lids resulting 
in their insufficient closure during sleep (Fuchs). 

Staphylococci are found in the pustules. Stubborn varieties 
may depend upon eczema seborrhoeicum of the face ; rarely the 
trichophyton fungus is found (blepharitis trichophytica of Mibelli). 

Treatment. — This differs with the type of the disease, but 
in all cases the refraction of the eye should be ascertained and 
any anomalous condition corrected with suitable glasses. This 
will often cure an ordinary hyperemia of the lid margin, but if 
it is not sufficient, in addition to soothing lotions, the daily use 
of an eye-douche is most serviceable, performed as follows : — 

A suitable vessel, to which is attached a rubber tube having at 
the lower end a small tin arrangement, containing many perfora- 
tions like the rose of a watering-can, is filled with water of a tem- 
perature of 68° F., and held a short distance above the head, the 
water being allowed to play for several minutes upon the closed 
eyelids. The douche may be made more acceptable by the addi- 
tion of a little eau de cologne, or alcohol. This method, recom- 



DISEASES OF THE EYELIDS. 1!>7 

mended by Koenigstein, is most efficacious. Stimulating salves 
do qoI yield good results in tliis variety, but the edges of the 
lids may be anointed with almond oil or vaseline. 

In the eases classified among the seborrheas, all crusts and 
scales should be removed by alkaline solutions (bicarbonate or 
biborate of soda, grs. viij-f Jj), or with a 5 per cent, solution of 
chloral (Gradle), and one of the following ointments applied once 
or twice daily : yellow oxide of mercury (gr. j— 3j), zinc ointment, 
or the salve advised by Gradle : — 

Milk of sulphur ...... 3 grains 

Resorcin ........ 3 grains 

Vaseline ........ 100 grains 

Great care must be exercised to remove the crusts from all 
the ulcerated varieties, either with the lotions which have been 
mentioned, or, after softening, with forceps, before the applica- 
tion of any salve. Red or yellow oxide of mercury, or dilute 
citrine ointment, is suitable. 

In chronic cases, all loose cilia should be extracted with epila- 
tiug forceps, and any deep ulcers should be touched with the 
point of a crayon of nitrate of silver, or pencilled with a solution 
of the same drug, or treated with a mixture of corrosive sublimate 
in glycerine (1 to 100 to 1 to 30, Despagnet). In severe forms, or 
when it is desirable to try other remedies, the following formulae 
will be found useful : — 

Diachylon ointment ...... 15 grains 

Vaseline ........ 240 grains 

Boracic acid 30 grains 

Simple ointment 300 grains 

Aristol 15 grains 

Vaseline ) ,. , „- . 

> ot each ...... 75 grains. 

Lanolin ) 

If the lachrymal passages are obstructed, they must be ren- 
dered patulous, and in all cases the anterior and posterior nares 
should be explored for disease. 

The constitutional remedies include iron, quinine, and, if struma 
is present, cod-liver oil and lacto-phosphate of lime, with iodide 
of iron or syrup of hydriodic acid. 

Blepharitis may be a mild affection and yield readily to treat- 



198 DISEASES OF THE EYE. 

ment ; or it may be stubborn, and require constant attention and 
frequent change in local measures to prevent deformities in the 
lid margins. 

Phthiriasis {blepharitis ptediculosa) occurs when the pediculua 
pubis or crab-louse forsakes its seat of predilection and finds a 
habitat among the eyelashes. The cilia appear sprinkled with 
a fine dark powder — the eggs of the parasites — which are usually 
found partially buried, head foremost, in the hair follicles. 
There is some itching and redness. The affection is comparatively 
rare, and in most instances has been observed in children. The 
lice may be removed by the application of blue ointment, or a 
careful pencilling with a strong bichloride solution. 

A parasite which in rare instances has been found in the hair 
follicles of the eyelids (Steida) and in the Meibomian glands 
(Majocchi) is the Demodex folliculorum. In one case the symptoms 
resembled those of blepharo-adenitis. Removal of the parasite 
resulted in cure. 

Syphilis of the Eyelids. — Syphilitic affections of the eyelids 
exist either as the primary sore, or as secondary or hereditary 
manifestations. A chancre usually appears on the area included 
by the lid borders and inner canthus, the tarsal conjunctiva and 
the cul-de-sacs. (DeBeck.) The lesion begins as a pimple which 
gradually develops into a characteristic, somewhat saucer-shaped 
ulceration, with rather rounded edges and indurated base. The 
lymph glands in front of the ear and at the angle of the jaw 
are enlarged., Contagion has often occurred by the application 
of the lips or tongue of an individual suffering from mucous 
patches in the mouth, as, for instance, in the act of kissing; or by 
the filthy practice of attempting to remove a foreign body with 
the tip of the tongue. Soiled fingers have also carried the con- 
tagion. 

It is possible to mistake the affection for a stye, suppuratiug 
chalazion, ulcerated tear-sac, vaccine ulcer, or small rodent ulcer. 

Treatment. — Locally, the ulcer may be dressed with black 
or yellow wash. As soon as positive secondary manifestations 
are sufficiently evident to settle the diagnosis, the ordinary anti- 
Bvphilitic remedies should be exhibited. 

The lesions of secondary syphilis upon the eyelids require no 
special description. 



DISKASF.S oF THK EYELIDS. 



199 



Among the later manifestations gummata of the skin of the 
lid, which break down into ulcers — so-called tertiary ulcers — are 
described. 

A papular eruption may appear upon the eyelids of children, 
the subjects of hereditary syphilis, shortly after birth. A form 
of blepharitis, characterized by sharply ulcerated spots, has been 
described as the result of hereditary syphilis, and in subjects of 
this dyscrasia, absence and falling-out of the eyelashes have been 
seen. The latter condition also arises during secondary syphilis. 

Tumors and Hypertrophies. — A variety of growths, cystic and 
solid, are found upon the eyelid and its border. Along the 
latter, warts or papillomata are common. These are benign, ex- 
cept when in elderly people through irritation they may take on 
an epitheliomatous nature. They should be cut off and their 
bases should be cauterized. 

Small clear cysts are common along the ciliary margin, often giv- 
ing rise to considerable irritation. They should be punctured. 

A reddish, wart-like mass may occur at the mouth of a Mei- 
bomian gland-duct. This is to be treated like an ordinary wart. 

Angiomas (Xaevi) are congenital growths, and exist either as 
bright red spots, or in the form of elevated cavernous growths. 
They should be dealt with early in their existence, lest they spread 
into the orbit. 

That operative interference should be practised which promises 
the least subsequent deformity to the lid. When small, they may 
be excised, or cauterized with 
nitric acid ; if of a larger vari- 
ety, their bloodvessel structure 
should be destroyed with the 
galvano - cautery or red - hot 
needles. Injections of liquor 
ferri subsulphatis are not to 
be recommended. 

Cutaneous corns (fibroma; 
moUuscuiii fibrosum) occur as 
connective-tissue new growths, 
either sessile or pedunculated, sometimes associated with numer 
ous similar tumors elsewhere on the body. 




Cornu cutaneum of the upper eyelid. 
(From a patient in the Jefferson Medi- 
cal College Hospital.) 



200 



DISEASES OF THE EYE. 



Neuromas, of the plexiform variety, and lipomas arc benign 
growths which should be removed by careful dissection. The 
latter growth sometimes appears in the form of an extensive 
accumulation of fat in the connective tissue of the lid, causing 
it to droop over the cornea, and produces the condition to which 
the name ptosis lipomatosis has been given. The mass should 
be dissected out, but complete mobility of the lid is not always 
regained, owing to failure in the power of the levator palpebral 



Fig. 73. 



Fig. 74. 




Congenital ptosis due to a hypertro- Epicanthus and congenital ptosis. 

phic condition of the skin of the eye- (From a patient in the Children's 
lid, and tumor formation. Hospital.) 

Rare forms of benign tumors are adenoma of the sweat-glands 
and their follicles, papilloma of the ciliary border, and enchon- 
droma of the tarsus. 

Xanthelasma (xanthoma) is a connective-tissue new growth, 
with fatty degeneration, usually seen in the form of narrow, 
semicircular patches, most common upon the upper eyelid-. 
although all four lids may be affected. The patches arc yellow 
or buff-colored, and on a level with the surrounding skin, or 
slightly raised above it. 

Excision, if this may be performed without producing ectro- 
pion, is the simplest method of treatment. The growth pro- 
duces no irritation. 



DISEASES OF THE EYELIDS. 201 

Chalazion (Meibomian cyst, tarsal tumor). — This is a small 
tumor or retention cyst, due to a chronic inflammation of a Mei- 
bomian gland and the tissue which surrounds it. The growth 
begins by retention of the secretion of the Meibomian glands, 
followed by a peri-adenitis and destruction of the tarsal carti- 
lage, with passage of the tumor towards the conjunctiva (internal 
chalazion), or to the skin (external chalazion). According to the 
rapidity of its development, the chalazion is either acute or chronic. 

( use. — The cause of chalazia is not known. They may be 
associated with inflammation of the border of the lid and stop- 
page of the duct of the gland. Individuals affected with these 
growths not infrequently have ametropic eyes, especially when 
tli<re is a tendency to recurrence in crops, like styes. They 
arc more common in adolescence than in youth, childhood, or in 
old age. Bacteria have been described, but they exist only in 
connection with suppuration in the cyst. 

Symptoms. — The tumor grows slowly, unless it is of the acute 
type, and forms a firm swelling attached to the tarsus. The 
skin usually is freely movable over it; on the conjunctival sur- 
face a discolored patch marks its position. Suppuration may 
take place in the cyst. 

An acute chalazion may be mistaken for a stye, from which it 
is to be distinguished by the more circumscribed character of the 
inflammation, and by the fact that the stye points in the edge of 
the lid ; and a chronic chalazion for a sebaceous cyst, from which 
it may be differentiated by the firmness of its attachment to the 
tarsus. Chalazia, small sarcomata of the lid, and even beginning 
glandular carcinoma have been confounded. 

Treatment. — It is sometimes attempted to produce resolu- 
tion by the inunction over the swelling of a resolvent ointment. 
The following may be tried: — 

Yellow oxide of mercury ..... 2 grains. 
Vaseline ) 



Lanolin > 



of each ...... 30 grains. 



Or— 



Iodide of cadmium ...... 10 grains. 

Vaseline 60 grains. 



The skin should first be prepared by frequent applications of 
hot Mater. 



202 ' DISEASES OF THE EYE. 

The only radical measure is removal by means of an incision, 
according to the method described on page 580. 

The malignant growths which appear upon the eyelids are 
sarcoma, carcinoma, in the form of epithelioma or of rodent ulcer, 
and lupus. 

Sarcoma occurs as a primary tumor in both upper and lower 
lids, and usually is seen in children. At first the growth is 
slightly elastic and the skin moves over it freely, but the ten- 
dency is to rapid growth, ulceration, and involvement of the 
orbit. The various types of sarcoma have been seen in this 
region, and the tumor has been known to follow a contusion. 

An early removal of the growth is urgently indicated, but 
even then local return or metastasis may follow. 

Carcinoma of the eyelid often appears in the form of rodent 
ulcer (Jacob's ulcer), which is a type of epithelial cancer, charac- 
terized by slow ulceration and non-involvement of the neighbor- 
ing lymph-glands, and is usually seen in elderly people. 

The growth begins as a pimple over which a crust appears. 
Gradually an ulcer forms, which slowly spreads with indurated 
and elevated edges, and if unchecked involves all the tissues and 
destroys the eyeball. Often many years elapse before the ulcer 
attains any considerable size. The most common point of origin 
is the inner end of the lower lid. 

The slow growth, and absence of lymphatic involvement, to- 
gether with the age of the patient, suffice to distinguish rodent 
ulcer from a tertiary syphilitic sore. 

It may be confounded with lupus; but the latter occurs in 
younger subjects, is more inflamed and less indurated, the ulcer- 
ations proceed from many points, and are generally associated 
with lupus elsewhere in the body. 

Instead of rodent cancer, an epithelioma with the ordinary 
clinical characteristics may attack the eyelid. (Figure 77). 
Glandular carcinoma, having its point of origin either in the 
Meibomian or in Krause's glands, is a rare form of cancer. 

Treatment. — Certain local remedies, as aristol, chlorate of 
potash, and injections of pyoktanin, have been recommended, 
but the proper treatment is excision. This must be undertaken 
at an early date, to prevent the necessity of extensive plastic 



DI8EA8ES <>l" THE EYELIDS. 203 

operations to replace the excised tissues. If the disease is ad- 
vanced. ( Janquoin's paste, chloracetic acid, scraping, or the actual 
cautery may be employed to check the ulceration. 

Fig. 75. 




Destruction of eyeball and orbital tissues by a rodent ulcer ; five years between 
the two stages. (From a patient in the Philadelphia Hospital.) 

Lupus Vulgaris is a cellular new gmwth composed of variously- 
shaped, reddish tubercles, which usually terminate in ulceration 
and extensive cicatrization. As this disease commonly appears 
on the face, it may also involve the eyelids. 

The process begins in youth, often before puberty, and is slow 
in its course. The ulcers are apt to start from a number of 
points which coalesce; their edges are soft, and the discharge is 
offensive. Syphilitic ulcers, on the other hand, are deeper, more 
excavated, with harder margins, and their course is more rapid. 

TREATMENT. — Local application of caustic paste, era-ion with 
a curette, and the actual cautery have been employed, and, at one 
time, injections of tuberculin. 



204 



DISEASES OF TIIK EYE. 



Lepra. — Leprosy attacks the eyelids very frequently. Accord- 
ing to Lopez two-thirds of the patients sutler from lesions in 
this region. These consist of anaesthetic patches of color slightly 
different from that of the surrounding integument, tubercles, loss 
of the eyelashes and eyebrows, and ectropion and entropion, the 
former occurring with extraordinary frequency. 



Fig. 76 



Fig. 77. 



^. 




From a photograph of a patient with 
syphilitic tarsitis, under the care of Dr. 
Randall in the Children's Hospital. 




Epithelioma of the eyelid. From 
a j>:it i«nt in the Jefferson Medical Col- 
lege Hospital. i 



Elephantiasis Arabum, or a chronic hypertrophic disease of 
the skin and subcutaneous tissue, has appeared in the upper 
eyelid in consequence of an injury, but may also he congenital. 
Elephardiam tdeangieetodea, or that disease which consists in a 
hypertrophy of the skin and connective tissue, together with 
fatty tissue and distended vessels, occurs in the upper eyelid a- a 
congenital affection. 



DISEASES OF THE EYELIDS- 205 

Tarsitis, or inflammation of the tarsus, is usually syphilitic in 
origin, and presents great thickening of the tarsus, owing to 
diffuse gummatous infiltrations. As a rule, it is chronic in 
course; in rare instances, an acute form has been described, As 
an idiopathic affection, the disease resembles a chronic marginal 
blepharitis, with the formation of crusts and ulcers at the mouths 
of the hair follicles, but differs from the latter condition by the 
presence of considerable thickening and induration of the tarsus. 

Treatment. — It' syphilitic, tarsitis is amenable to the ordi- 
nary remedies ; it* idiopathic, much the .-nine treatment described 
in connection with chronic blepharitis is applicable, especially 
the use of resolvent ointments. 

Blepharospasm, or an involuntary contraction of a portion 
or of the whole of the orbicularis palpebrarum, appears either as 
a clonic or a tonic cramp. 

The former variety, in its simplest forms, consists in a twitching 
of a few fibres of the muscle, most commonly in the lower lid, 
very annoying, and often the cause of undue alarm. It arises 
from the strain of ametropia, prolonged eye use, and deficient 
amplitude of accommodation. 

The treatment comprises the prescription of glasses, and a 
general tonic, a very suitable one being an elixir of quinine, iron 
and strychnia, provided the last remedy does not aggravate 
the affection, in which case it may be omitted from the combina- 
tion. In stubborn cases, fluid extract of gelsemium will afford 
relief. Conium internally, and the extract locally, have been 
recommended. 

Children are often affected, especially during their early school 
years, with undue winking of the eyelids, associated, at times, 
with jerky movements of the facial and other muscles. This 
form of nervous disorder is designated by Weir Mitchell "habit 
chorea" 1 Almost invariably blepharitis, follicular conjunctivitis, 
and errors of refraction and insufficiencies of the external f\v 
muscles will be found as exciting causes. Suitable glasses and 
appropriate local remedies, together with the exhibition of 
Fowler'.- solution, will usually bring about a curt'. 

Tonic cramp of the orbicularis follow- the introduction of 

1 Gowers gives the name " habit spasm" to the same affection. 



206 DISEASES OF THE EYE. 

foreign bodies into the eye, the presence of inflammations of the 
cornea and conjunctiva, and fissures at the angles of the lids. 

More rarely, a persistent lid cramp occurs, without obvious 
cause, and is unrelieved for weeks and even months. When the 
eyes arc finally opened there may be temporary blindness, with- 
out corresponding ophthalmoscopic changes ; or permanent loss 
of vision, with gross lesions in the eye-ground. 

Tonic cram j) appears to be a form of reflex action, arising 
through irritation of the peripheral trigeminal filaments. The 
blindness which has been observed in certain instances has been 
explained as cortical in nature, owing to the long absence of 
peripheral stimulation, or as an example of the "forgetting voli- 
tion" of the sensory perceptions, analogous to the suppression of 
the image in alternating strabismus. (Samelsohn.) If gross changes 
appear, these have been explained by pressure of the closed lids 
upon the ball. 

The treatment demands the removal of any peripherally exciting 
cause — fissure, foreign bodies, phlyctenules, etc. Hypodermics 
of morphia have been used to control the trigeminal irritation, 
and in bad cases section of the supraorbital nerve has been 
performed. Conium and gelsemium in the form of the fluid 
extract may be tried. They should be pushed to the point of 
tolerance. 

Ptosis (/>/epharopto.s>is) is that condition in which the upper lid 
droops entirely or partially over the eyeball, and cannot be vol- 
untarily raised. It is either congenital (page 189), or acquired 
by reason of the development of fatty or other accumulations in 
the connective tissue of the lid (page 200), or it arises from para- 
lysis of the oculo-motor nerve ; in rare instances from lesion of 
its cortical centre. In some cases of unilateral congenital ptosis, 
usually on the left side, while the eyelid cannot be voluntarily 
raised, it is elevated when the jaw is moved during eating (con- 
traction <i|' the levator in association with the external pterygoid). 
(See also Ocular Palsies.) 

Treatment. — The medicinal treatment calls for the exhibition 
of those remedies which control the supposed cause of the palsy — 
mercury and iodides in syphilis, salicylic acid in rheumatism. 
The surgical treatment will be found on page 581. 



DISEASES OF THK EYELIDS. 



207 



Lagophthalmos, or an inability to close the eyelids, is either 
paralytic or non-paralytic, and usually results from paralysis of 

the facial nerve, as in Bell's palsy, but also occurs in tumors of 
the orbit, exophthalmic goitre, and staphyloma. The highest 
grade of lagophthalmos appears as a congenital defect (page 188). 

The chief danger of the affection is ulceration of the cornea 
from exposure, rendered all the more certain should disease of 
the trigeminus also exist. 

Treatment. — In paralytic lagophthalmos the primary cause 
of the affection must be treated ; in the non-paralytic varieties, 
and in any form in which the vitality of the cornea is threatened 
by its exposure, the operation of tarsorrhaphy may be employed. 
(See page 583.) 

Symblepharon, 1 or a cohesion between the eyelid and the ball, 
may be complete or partial, acquired or congenital (page 188). 
The most usual causes are injuries, especially burns with acids 

Fig. 78. 




Symblepharon, the sequel of purulent conjunctivitis. From ;i patient iu the 
Philadelphia Hospital. 

or lime. Symblepharon also follows diphtheritic conjunctivitis, 
trachoma, pemphigus, and occasionally purulent ophthalmia; but 
the shortening of the conjunctival sulcus, which occurs by a spe- 

1 Symblepharon really belongs to diseases of the conjunctiva, but is conven- 
iently inserted in this place. 



208 DISEASES OF THE EYE. 

cies of drying of the conjunctiva, presently described, must not 
be confounded with a true symblepharon. The attachment may 
be merely slight bands between the conjunctival surface of the 
lid and ball, or, in the more complete cases, the cornea may also 
be involved in the cicatricial union, and vision seriously dis- 
turbed. The lower lid is most usually involved in the process ; 
the upper may also participate. (Fig. 78.) 

Ankyloblepharon, or that condition in which the borders of 
the two lids have grown together, may be congenital or acquired, 
and, like the preceding affection, partial or complete. 

The same causes which originate symblepharon are here active, 
and varieties are described in which the union takes place, not by 
a growing together of the lids, but by the organization of a mem- 
brane, the result of croupous conjunctivitis. 

Blepharo-phimosis is the name given to that condition which 
arises through a contraction of the outer commissure of the lids, 
and results in shortening of the palpebral fissure. 

It is commonly seen in cases of long-standing conjunctivitis 
with irritating secretions ; for instance, in chronic blennorrhcea, 
and in some of the forms of granular lids. 

Treatment. — After an injury, or during the course of a 
local disease, likely to result in one of these complications, 
scrupulous care must be exercised to avoid it. The formation 
of granulation tissue may be broken up with a probe, and it 
has been advised to place a piece of gold-beater's skin between 
the lid and the ball to prevent adhesions. It is doubtful if the 
latter expedient will often prove successful. 

The surgical treatment of these affections is described on page 
596. 

Trichiasis; Distichiasis. — Trichiasis is, that affection in which 
the lashes are misplaced and turn inward against the eyeball ; 
distichiasis is that condition in which incurved rows of supple- 
mentary cilia are developed from the intermarginal part, close to 
the opening of the tarsal glands. 

The most usual causes of trichiasis are chronic inflammations of 
the lid borders — blepharitis, and granular conjunctivitis. Distichi- 
asiSj in rare instances, is congenital, or develops about the age of 



DISEASES OF THE EYELIDS. 209 

puberty, but occurs also a* the result of the diseases named. 1 
The cilia rubbing against the cornea produce constant irritation, 
and may lead to ulceration. 

Treatment. — If not too numerous, the lashes having; a faulty 
direction should be removed with cilium forceps, and when they 
grow again, the procedure repeated ; their reappearance may some- 
times be prevented by destruction of the hair follicles by galvano- 
puncture. ( >ther operations consist of strangulation of the roots 
of the incurved lashes by a subcutaneous ligature, excision, and 
the various modifications of single and double transplantation of 
the entire ciliary border. (See Operation Chapter.) 

Entropion, or inversion of the lid, like the former affection, is 
most commonly caused in an organic form by granular lids, and 
also follows essential shrinking of the conjunctiva and diph- 
theritic conjunctivitis. Entropion and trichiasis are often asso- 
ciated . 

Two other varieties of entropion are described, muscular and 
bulbar. The former is sometimes present at birth from undue 
development of the orbicularis, and also occurs in a spasmodic 
type, under the influence of conjunctivitis, keratitis, and foreign 
bodies ; the latter is a falling in of the lids when the eyeball is 
shrunken or absent. 

Treatment. — The spasmodic varieties will usually subside 
if the exciting cause can be removed. Painting; the lid with 
flexible collodion, which by its contraction draws out the in- 
verted border, or fastening this with a strip of adhesive plaster, 
or pinching up a longitudinal fold of skin and muscle with a 
serre-jme and keeping it in place, occasionally changing the posi- 
tion of the instrument to avoid irritation, are methods advocated 
in the treatment of temporary entropion. The organic varieties 
of the disorder require one or other of the operations described 
on page 587. 

Ectropion, or eversion of the lid with exposure of the conjunc- 
tival surface, is either partial or complete. The disorder is 

1 Raehlmann believes that trichiasis hairs, or "false cilia," are developed 
from the epithelial covering of the lid margin in consequence of marginal ble- 
pharitis, the result of granular conjunctivitis. 
14 



210 



DISEASES OF THE EYE. 



divided into the acute or muscular, and the chronic form, or that 
which results from organic changes. 



Fig. 79. 



Fig. 80. 





Ectropion of the upper lid, the result 
of an injury to the brow and subsequent 
caries of the margin of the orbit. ( From 
a patient in the Philadelphia Hospital.) 



Ectropion of the lower lid, the re- 
sult of a wound from the tine of a 
fork. (From a patient in the Chil- 
dren's Hospital.) 



Acute ectropion usually occurs in children with conjunctivitis, 
and in diseases of the cornea with blepharospasm, when the 



Fig. 81. 



Fig. 82. 





Ectropion of the Lower lid caused by- 
caries of the malar bone. I From a pa- 
tient in the Philadelphia Hospital.) 



Ectropion of the upper lid from syph- 
ilitic periostitis of the orbit. (From a 
patient in the Philadelphia Hospital.) 



lids, during examination, become everted and remain so until 



DISEASES OF THE EYELIDS. 211 

replaced. One form of partial muscular ectropion is produced 
by facia] palsy. 

The common causes of the second, or chronic form of ectro- 
pion, arc wounds, especially such as are caused by dog-bites, by 
laceration of the lid by a sharp instrument, by burns and sub- 
sequent cicatricial contraction, by chronic inflammatory condi- 
tions of the ciliary margin, by ulceration of the lids as in lupus, 
and by caries of the orbital border and malar bone. The lower 
lid is more frequently involved than the upper, but ectropion is 
also -ecu in the latter. 

Treatment. — This varies with the type and degree of the 
ectropion. In the spasmodic forms, simple replacement of the 
everted lids suffices; in slightly marked grades, with some ever- 
sion of the lachrymal punctum, the canaliculus should be partly 
slit, and, if necessary, the nasal duct should be probed. The 
organic type- of the disorder require a plastic operation for the 
relief of the deformity. (See Operation Chapter.) 

Certain diseases of the eyelids are comprised in a group of 
functional disorders of the sebaceous and sweat glands. 

Seborrhcea, or that functional disorder of the sebaceous glands 
during which their secretion is altered, and forms an oily coating 
on the skin, sometimes accompanied with crusts and epithelial 
scales, is also seen upon the eyelids. It is usually associated with 
a similar process in the scalp and eyebrow, and when specially 
localized upon the ciliary margins, creates one of the forms of 
blepharitis already described. 

Treatment. — Proper hygiene, cod-liver oil, iron and arsenic, 
removal of the accumulated sebum by frequent washings, and 
the application of sulphur and mercurial ointments comprise the 
most efficient methods of treatment. 

Milium. — Milia, or small yellowish elevations, consisting of an 
accumulation of sebum within the distended but closed sebaceous 
glands, are common upon the eyelids. They often develop about 
the age of puberty. 

They are caused by improper care of the skin, and may be 
connected with general constitutional disturbances, dyspepsia and 
constipation. They should be opened with a knife or needle, and 
the contents evacuated. 



212 DISEASES OF THE EYE. 

Molluscum contagiosum {M. sebaceum) is a disease of the 
sebaceous glands (according to some authors, of the rete muco- 
sum), characterized by the appearance of rounded papules, about 
the size of a pea, and of a waxy color. The eyelids are a favorite 
situation. 

The disorder occurs chiefly among ill-nourished children, is 
believed by many to be contagious, and may arise as an epidemic 
in homes and asylums. Recent investigations seem to show that 
the affection is caused by a parasite belonging to the class cocddia, 
and really is a form of contagions epithelioma. 

Treatment. — Each molluscum should be incised, and its con- 
tents forced out. 

Ephidrosis (Jii/peridrosis), or an increased flow of sweat, has 
in rare instances been observed as a local disorder of the sweat- 
glands of the eyelids. In cases of unilateral sweating of the 
face, the lids necessarily participate. 

Chromidrosis, or the formation of a variously colored secretion 
from functionally disordered sweat-glands, is sometimes located 
upon the eyelids. It then receives the name of palpebral chro- 
midrosis, and consists of a bluish-black discoloration, usually 
upon the lower lid, which is somewhat oleaginous and can be 
wiped away. 

It is probably genuine in rare instances ; in others, it is believed 
to be either a fraud practised by hysterical subjects, or due to 
the deposit of dust upon the surface of the skin affected with 
seborrhcea. Young women are usually those affected. 

The treatment should consist in general invigorating methods 
calculated to remove ansemia, debility or nervous disturbances. 
Locally, lead water and glycerin are recommended. 

Sebaceous Cysts occur in the eyelids, most frequently in the 
outer part, and also in the eyebrow. In the latter situation, they 
sometimes are deeply seated, tightly adherent to the periosteum, 
and may extend some distance into the orbit. Dermoid cysts are 
also found in this region. Their removal by an ordinary dissec- 
tion is usually unattended with difficulty. 

Injuries of the Eyelids. — Incised, lacerated, and contused 
wounds, oedema, emphysema, and ecchymosis are the ordinary 
results of accidents and injuries to the eyelids. 



DISEASES OF THE EYELIDS. 213 

Wounds. — The type of a wound depends largely upon the char- 
acter of the implement which has inflicted it, and may vary from 
a simple and superficial incision to a deep cut which penetrates 
the tissues of the lid, and injures the structures of the eyeball lying 
beneath. In like manner, a laceration may be small and unim- 
portant, or may be so extensive as to tear the eyelid from its 
attachments. Incised wounds in the line of the direction of the 
fibres of the orbicularis result in the least visible scar, owing to 
the absence of gaping. 

Treatment. — Accurate approximation of the wound should 
be secured with catgut or silk sutures, and scrupulous antisepsis 
should be followed. Even considerable laceration may heal with 
very little deformity if neat adjustment is secured. 

Oedema usually occurs as the sequel of a blow, owing to the 
loose connective tissue of the eyelids, which readily admits of 
distension. 

CEdema not the result of an injury, is seen with severe inflam- 
mations of the conjunctiva, as part of a general condition (renal 
or cardiac), with purulent disease of the sinuses or antrum, and 
sometimes in a fugitive aud not infrequently recurrent form. 
The last variety has been observed with migraine, at the time 
of the establishment of menstruation, and spontaneously, with- 
out apparent cause. Some instances are analogous to urticaria. 

Treatment. — The application of evaporating lotions, like 
dilute lead-water and laudanum, associated, if the swelling is 
great, with a pressure bandage, is a measure which will afford 
relief. If a general cause is at the root of the trouble, this must 
receive appropriate treatment. 

Emphysema of the lids is observed when a fracture of the orbit 
permits air to escape into the cellular tissue, through a communi- 
cation thus produced with the ethmoidal or frontal sinus. A soft 
swelling, crackling to the touch, is the result, which increases in 
degree when the patient blows his nose and forces the air through 
the fissured bone. The eyelids may participate in the emphysema 
of the neck and face, sometimes seen after tracheotomy, or after 
stab-wounds of the chest. 

Ecchymo8i8 of the lids, or a collection of blood in the connective 
tissue, in its simplest variety constitutes the familiar " black eye," 



214 DISEASES OF THE EYE. 

the common result of a blow. A gradual absorption of the 
effused blood takes place, requiring a week or longer for its 
completion, but the skin may retain its black and blue stain for 
a greater period of time. 

Ecchymosis results also in some cases of fracture of the base 
of the skull, and may be associated with emphysema, if a fracture 
has involved the frontal or ethmoidal cells. 

Treatment. — Emphysema will gradually subside without 
local treatment; if the swelling is severe, it has been recom- 
mended to prick the tissues and allow the air to escape. 

Ecchymosis should be treated with frequent applications of 
cold water, arnica, lead-water and laudanum, or diluted white 
extract of hamamelis. If discoloration remains for a long; time, 
the "eye may be painted." The practice of applying leeches, or 
incising the swollen lid and sucking out the contained blood, is to 
be condemned. 

Burns of the Eyelids are commonly inflicted with hot water, 
caustics (lye and lime), acids, or by the explosion of powder. 

The first agent produces the ordinary vesication, and the treat- 
ment should consist in the application of oil, while the pain may 
be materially relieved by using locally a lotion of carbonate of 
soda, or, better, the moistened powder itself. 

Burns caused by the other materials are especially dangerous 
on account of the almost invariable involvement of the cornea 
and conjunctiva. (See page 257.) Immediately after a powder 
burn, all loose powder should be removed, and if possible each 
grain picked out of the skin with a fine needle, or, according to 
Edward Jackson, destroyed by touching it with a fine electro- 
cautery needle. The application for ordinary burns may then 
be used. 



I>I-I.A-I> OF THE CONJUNCTIVA. 



215 



CHAPTER VI 



DISEASES OF THE CONJUNCTIVA. 

Congenital Anomalies of the Conjunctiva. — In addition to 
dermoid tumors (page 253) certain thickenings of the conjunctiva, 
of congenital origin, have been reported. The latter resemble 
pterygia, and extend between the fissures of the lid (Strawbridge). 
It' necessary, excision could be performed. 

Hyperaemia of the Conjunctiva {Dry catarrh; Hypercemia 
palpebrwris) is characterized by an injection of the vessels, chiefly 
of the palpebral conjunctiva, but rarely affecting the ocular ex- 
pansion of the membrane. The posterior conjunctival vessels 
(System I.) are involved, but not to the same extent that they 
are in conjunctivitis. Both an acute and chronic form exist. 

Causes. — The strain of 
ametropia furnishes a large • 83- 

contingent of these cases, 
while others arise when the re- 
fraction error is insufficiently 
or improperly corrected. Be- 
ginning presbyopia, especially 
in those people who are disin- 
clined to use glasses, and hyper- 
emia of the conjunctiva are 
often associated; it also occurs 
with incipient cataract and slight 
opacities of the cornea, as the result of the effort to obtain clear 
images. 

Local irritants, as dust, foreign bodies, tobacco smoke, cold 
winds, etc. are common causes, and the abuse of alcohol origi- 
nates many cases. 

Nasal catarrh, lachrymal obstruction and marginal blepharitis 
are frequently accompanied by chronic hyperemia of the conjunc- 




Congestion of the posterior conjunc- 
tival vessels. (Guthrie.) 



216 DISEASES OF THE EYE. 

tiva, which is much aggravated by the establishment of an acute 
coryza, or a condition like "hay fever." 

finally, certain acute hyperemias, which may be recurrent, 
appear in the form of vaso-motor disturbances, and are seen 
under the influence of general diseases, especially gout. 

Symptoms. — Direct inspection reveals the congestion of the 
vessels, not sufficient to produce the velvety appearance seen in 
ophthalmia, and unaccompanied by any discharge. Slight swell- 
ing of the conjunctival follicles may be present. There are 
photophobia, some lachrymation, a hot, stinging sensation, aggra- 
vated by use of the eyes, which readily " water" and grow 
uncomfortable, especially by artificial light. , 

Treatment. — This calls for the correction of any refractive 
error and careful examination into the accuracy of glasses, pro- 
vided they are worn by the affected individual. 

Removal of exciting local causes, and attention to the anterior 
and posterior nares are necessary. Patency of the canaliculi and 
of the lachrymal passages should be secured. 

Locally, boric acid (gr. x-f,5j), or biborate of soda gr. v, cam- 
phor water f§j and distilled water f §j, may be applied. More 
active astringents, as alum, tanuin, and zinc are sometimes em- 
ployed, and stimulating drops, as equal parts of tincture of 
opium and water, or boric acid solution, to which a few drops 
of alcohol have been added, are useful. Nitrate of silver is not 
advisable. Douching the eyes with hot or cold water is a valu- 
able adjuvant. 

If there is reason to suspect any general trouble, for example 
gout, this must receive attention, and in those varieties believed 
to be of vaso-motor origin a mixture of tincture of nux vomica 
and fluid extract of ergot may be exhibited. 

Conjunctivitis. — The conjunctiva is liable to various grades 
and types of inflammation which have certain symptoms in com- 
mon : (1) Photophobia, not constantly present in all varieties, but 
commonly seen at some time during the course of the complaint; 
(2) increased and usually altered secretion ; (3) a changed appear- 
ance in the membrane, varying from a general injection of tne 
blood-vessels, and slight velvety opacity, to the development of 
special pathological products, or the formation of false membrane. 



DISEASES OF THE CONJUNCTIVA. 217 

The generic term "conjunctivitis" ( ,- ophthalmia " of the older 
writers) is applicable to this entire group of diseases. 

Simple Conjunctivitis (Catarrhal, Acute, or Muco-purulent 
Conjunctivitis, or Ophthalmia). This is an inflammatory disease 
of the conjunctiva characterized by congestion, loss in the trans- 
parency of the palpebral conjunctiva, some dread of light and 
spasm of the lids, and a discharge sufficient only to glue the lids 
in the morning, or free and muco-purulent. 

Causes. — The disease is commonest in warm and changeable 
weather, and, if the secretion is free, it is markedly contagious, 
and the affection will pass rapidly from one member of a house- 
hold to another. Micro-organisms are present in severe types 
and may explain the contagion ; neglected hyperemias and the 
presence of follicular granulations increase the susceptibility to in- 
fection, and scrofulous subjects are peculiarly liable to the disease. 

The etiolog-v is made evident bv observing- certain varieties : 

Associated conjunctivitis is seen with eczema, facial erysipelas, 
impetigo contagiosa, nasal catarrh, bronchitis, and constitutional 
disorders like typhoid fever and rheumatism. Among these 
may be included exanthematous conjunctivitis, which accom- 
panies or follows measles, scarlet fever, and smallpox. 

Mechanical conjunctivitis results from exposure to wind, dust, 
and traumatism (toxic conjunctivitis, see page 249). 

Symptomatic conjunctivitis may arise from the strain of ame- 
tropia, and is analogous to ordinary hyperemia. 

Finally, there is a special conjunctivitis, known as epidemic con- 
junctival catarrh, or acute contagious conjunctivitis, in which the 
process is more particularly located upon the retrotarsal folds. 
In this group may be included that form vulgarly known as 
"pink eye," and commonly seen in the spring and fall. Acute 
conjunctivitis is due to a bacillus isolated by Dr. John E. Weeks, 
of Xew York. Corneal complications occasionally occur in this 
form of conjunctivitis (Morax). 

Symptoms. — The secretion is at first watery and by running 
over the edge of the lids may excoriate the surrounding skin, 
which shows injection of its superficial veins. In certain indi- 
viduals the lids, especially along their palpebral margins, are 
slightly oedematous. 



218 DISEASES OF THE EYE. 

The secretion soon becomes mucous or muco-purulent, and, 
according to the grade of the inflammation, gathers in a slightly 
frothy material only at the commissural angles, or is very freely 
secreted, and when it dries, glues the borders of the lids and mats 
the cilia together. 

Inspection of the retrotarsal folds may reveal the presence of 
long strings of mucus or muco-pus. There are a general hyper- 
emia and loss in the transparency of the tarsal conjunctiva, in 
which the posterior conjunctival vessels (System I.) are con- 
cerned, and later of the fornix, caruncle, and semilunar folds. 

In severe types the entire conjunctiva is deeply injected, and 
small hemorrhages may be observed, the swelling of the mem- 
brane being noticeable in opaque, velvety layers, especially in 
the region of the retrotarsal folds, while the bulbar conjunctiva 
is chemotic. The lids are glued together in the morning, the 
eyes are hot and heavy, and feel as though they contained sand. 

Although vision is not usually affected, some secretion may 
be adherent to the cornea and produce the same haziness in sight 
that would be present on looking through a dirty glass ; and arti- 
ficial lights, which are most uncomfortable at all times, appear 
fringed with colored borders. 

Photophobia may be entirely absent, or exist in marked de- 
gree, most often in those varieties which complicate measles, or 
are associated with the development of small superficial ulcers on 
the cornea. All ages of life are liable to catarrhal conjunctivitis, 
but the majority of cases are seen in children and young people. 

Prognosis and Duration. — The prognosis is perfectly good, 
and the process will usually subside in from one to two weeks. 
Commonly both eyes are affected, the one a few days in advance 
of its fellow. The affection through neglect, however, may prove 
exceedingly troublesome, and in the epidemic varieties, tends to 
attack all members of a household, a fact which in asylums and 
similar institutions may prove of serious import, especially if the 
severe types, not readily separated from forms of purulent oph- 
thalmia, are prevalent. 

Treatment. — This consists first in search for the cause and 
the alleviation of associated conditions. The patient must be 
removed from the influence of dust, cold winds, tobacco smoke, 



DISEASES OF THE CONJUNCTIVA. 219 

and the like ; the under surfaces of the lids should he examined 
for foreign bodies, and their borders for misplaced cilia. In the 
earlier stages cold compresses are agreeable and suitable, but 
later, frequent bathings with hot water are more acceptable. At 
first a solution of boric acid (as collyrium or spray — gi*. x-fsj) is 
useful. The eye should be frequently washed with water and 
Castile soap. 

A- -non as the discharge becomes mucous or muco-purulent, 
and the velvety opacity of the conjunctiva forms, a stronger so- 
lution of boric acid, to which a few grains of common salt may 
he added, is advisable; and the everted lids should be painted 
with a weak solution of nitrate of silver (gr. ii-v-fsj). In se- 
vere types, with a considerable discharge, bichloride of mercury 
(gr. f— Oj) is a good collyrium. 

Other topical medications which have found favor are alum 
(gr. iv-viii-fSj), sulphate of zinc (gr. ii-fsj), which may be suit- 
ably combined with boric acid, biborate of sodium (gr. iv— viii : 
f.sj). peroxide of hydrogen, Panas's fluid, creolin (1 per cent.), 
and other antiseptic collyria. Should the thickening of the retro- 
tarsal folds prove stubborn, these may be touched with an alum 
crystal, or a solution of tannin and glycerin. Atropine is not 
usually necessary, unless a corneal ulcer complicates the affection. 

The eyes may be protected with smoked glasses, but under 
no circumstances should they be bandaged or be covered with 
poultices of tea-leaves (which of themselves may produce con- 
junctivitis — " tea-leaf conjunctivitis"), bread and milk, scraped 
potatoes, and the like. It should be remembered that meddle- 
some domestic medication of this sort may change a simple oph- 
thalmia into a serious and purulent inflammation. 

At the outset a laxative, followed by full doses of quinine, 
is indicated ; any associated disease of which the conjunctivitis 
may be a symptom, e.g. rhinitis, requires the usual treatment. 
Proper hygiene, fresh air, strict cleanliness, and protection from 
contaminated towels, etc., are evident indications. 

Purulent Conjunctivitis (Acute Blennorrhoea of the Conjunc- 
tion is described under two forms, according as it occurs in the 
new-born (ophthalmia neonatorum), and in adults (gonorrhceal 
conjunctivitis or ophthalmia). 



220 DISEASES OF THE EYE. 

Conjunctivitis Neonatorum [Ophthalmia Neonatorum). — 
This is an inflammation of the conjunctiva, characterized in its 
usual form by great swelling of the lids, serous infiltration of the 
bulbar conjunctiva, and the free secretion of contagious pus. 

Causes. — The affection is caused by the introduction into the 
eye of the infecting material, from some portion of the genito- 
urinary tract of the mother, at the time of or shortly after birth. 
The majority of cases, and all severe forms, are associated with 
a special micro-organism — the gonococcus of Neisser. Excep- 
tionally, inoculation occurs in utero, owing to the penetrating 
power of the gonococcus, or to infection after rupture of the 
membranes (ante-partum conjunctivitis). 

Inasmuch as this micro-organism is not invariably present, 
two forms of the disease have been distinguished — a severe type, 
supplied with the micro-organism, with a tendency to increase in 
severity and invade the cornea ; and a milder type, non-specific, 
with a tendency to recover. Hence a virulent vaginal discharge 
is not necessary to produce this condition, except in intense de- 
gree, and it probably may arise from the contamination of any 
muco-purulent discharge during birth, and from injudicious in- 
travaginal antisepsis with strong solutions of mercuric chloride. 
Careless bathing of the child after birth, and the use of soiled 
towels and sponges, are fruitful sources of infection. Contact 
with the lochial discharge may originate the disorder, although 
inoculation with healthy lochia has failed to produce the disease. 

The exact time of inoculation has not been determined. In- 
fection is more likely to occur in face presentations and during 
retarded labors. Boys are attacked more frequently than girls. 
The disease is said to be more common during summer months 
in cold climates ; in hot countries, during the spring and autumn. 

Symptoms. — Ophthalmia neonatorum usually begins on the 
third day after birth, but may set in as early as from twelve to 
forty-eight hours after inoculation, or, when it is the result of a 
secondary infection from soiled fingers, sponges or clothes, be 
delayed to a much later date. Almost always both eyes suffer, 
the one being earlier, and frequently more decidedly affected 
than its fellow. 

Four stages of the disease are common, but, as these vary in 



DISEASES OF THE CONJUNCTIVA. 221 

different cases, and more or lcs> rapidly shade one into the other, 
no very sharp lines need be drawn. 

A slight redness of the conjunctiva, with a trifling discharge 
in the corner of the eye, is rapidly succeeded by great, cushion- 
like -welling of the lids, with intense chemosis and congestion of 
the conjunctiva, accompanied by severe pain and discharge. The 
surface of the swollen lid is hot, dusky red, and tense; the upper 
lid overhangs the lower, and at first can only with difficulty be 
everted. The discharge, which in the beginning is slightly tur- 
bid, soon changes to a yellow or greenish yellow pus, and is 
secreted in great quantities. 

If the lids are everted during the first day or two of the dis- 
ease, tlx- conjunctiva will be found to be swollen, red, and vel- 
vet}-, and that upon the eyeball intensely injected ; upon the 
surface easily-detached flakes of lymph are found ; later, the con- 
junctiva becomes rough and of a dark-red color, spots of ecchymo- 
sis appear, or it is succulent and bleeds easily. Marked chemosis 
and infiltration of the ocular conjunctiva succeed, forming a hard 
rim ; at the bottom of the crater-like pit thus produced, the cornea 
may be seen. The thick, cream-like discharge increases, and either 
flows out from beneath the overhanging upper lid on to the 
cheek, or is packed up in the conjunctival cul-de-sac. (Fig. 84.) 

The lids now may lose much of their tense character, and can 
be more easily everted ; the conjunctiva is puckered into folds 
and papilla-like elevations, and the discharge contains an admix- 
ture of blood and serum. Gradually the disease declines, and in 
from six to eight weeks the discharge ceases. The relaxed pal- 
pebral conjunctiva is thick and granular, looking like the granu- 
lation-tissue which surrounds wounds. The ocular conjunctiva 
i? also thickened, and positive cicatricial changes may remain. 

The chief risk is destruction of the vitality of the cornea, 
the danger of which is materially increased if this membrane be- 
comes lustreless, dull, and hazy within the first day or two of 
the disease. Frequently small, oval ulcers form near the limbus, 
either transparent or surrounded by an area of cloudy infiltra- 
tion, which rapidly increase in size; or larger areas of ulcera- 
tion develop in a more central situation. In many mild cases the 
cornea escapes without harm. The changes which take place 



222 DISEASES OF THE EYE. 

in the cornea are due in part to strangulation of its nutrient 
vessels by the swollen tissue, but largely to direct infection by 
the discharge. 

Fig. 84. 



df 





Conjunctivitis neonatorum. From a patient iu the Philadelphia Hospital. 

After the formation of a corneal ulcer, either its healing and 
regeneration of the corneal tissue takes place, or else perforation 
occurs. 

The result of perforation will depend upon the amount and 
character of the destruction of the corneal tissue. When the 
ulcer is central and perforates, the aqueous humor escapes, the 
lens is pressed forward against the posterior surface of the 
cornea, and the opening becomes closed with lymph. This 
renders the re-collection of the aqueous possible, and, when it 
occurs, the lens returns to its proper position, carrying with it 
upon the anterior capsule a little mass of lymph. Thus the 
formation of a pyramidal cataract results. (See page 396.) 

Perforation of an ulcer peripherally situated, especially below, 
is followed by adhesion of the iris to the opening. The aqueous 
escapes, and, as the iris and the lens fall forward, the former 
becomes entangled in the perforation, and is fixed by inflammatory 
exudation. The adhesion is either on the posterior surface, or in 



DISEASES OF THE CONJUNCTIVA. 223 

the cicatrix, and the resulting dense white scar receives the name, 
adherent leucoma. 

It' the region of the scar is bulged forward because it is unable 
to resist the intraocular tension, anterior staphyloma results. 
Extensive sloughing of the corneal tissue, with total prolapse of 
the iris, matting together of the parts by exudation, and protru- 
sion of the cicatrix, constitute a total anterior staphyloma. 

Finally, perforation may be followed by inflammatory involve- 
ment of the ciliary body and choroid, and the rapid destruction 
of the eye through panophthalmitis, or a slower shrinking of the 
tissues, with atrophy of the bulb. Dense opacity occasionally ap- 
pears in the cornea during convalescence, and may go on to ulcer- 
ation, or clear up perfectly. It may arise with great suddenness, 
and, when it occurs in the lower half of the cornea, a deep in- 
dentation, owing to the pressure of the margin of the lid, is likely 
to occur. 

The appearance of the conjunctiva differs materially in different 
cases. Its surface may be covered over, not merely with easily- 
detached flakes of lymph, but with a gray, false membrane. 
More rarely, a deep infiltration develops, like that seen in diph- 
theritic conjunctivitis. 

Restlessness, fever, and other constitutional disturbances are 
sometimes present, and synovitis of the knee and wrists may 
arise, of the same character as similar complications occurring in 
adults during gonorrhoea. 

Ophthalmia neonatorum does not always follow this course, 
because the term is made to include affections of the conjunctiva 
in the newborn, other than the types just described — mild catarrhal 
ophthalmias, hyperemias, and that variety which, according to 
Noyes, presents the character of a granular, rather than of a 
purulent conjunctivitis, and which may continue for weeks with- 
out danger of corneal complication. 

Some hyperemia of the conjunctiva, with a little yellowish 
discharge in the corners of the eye, and slight swelling of the 
lower lid, is common in babies for a few days after birth, and 
may be attributed either to uncleanliness, or to change of tem- 
perature. 



224 DISEASES OF THE EYE. 

Diagnosis. — The onset and character of the disease, its symp- 
toms and course, render a mistake in regard to its nature prac- 
tically impossible. Close attention should be given to what at 
first appears to be a trivial inflammation in the eyes of a new- 
born child, because a virulent and destructive inflammation may 
follow with great rapidity. 

Prognosis. — This is always grave, but with competent medical 
attendance, if the eye is seen while the c<>rn<<t is still clear, except 
in diphtheritic types and those with inherent malignancy (Ran- 
dall), the majority of cases should be brought to a successful 
termination. Hence the attendants of new-born children should 
be compelled to seek medical advice as soon as conjunctival 
trouble appears, for delayed or improper treatment means 
sloughing of the cornea, when no form of medication can do 
more than relieve the violence of the inflammation, which, when 
it subsides, leaves the child with sight hopelessly marred, perhaps 
destroyed. 

Prophylaxis. — The present high standard of scientific mid- 
wifery includes such cautious antisepsis during labor, that the 
risk of contamination is distinctly less than in former times, but 
still some preventive method should be employed. 

Crede's plan is commonly adopted. This consists in dropping 
into the conjunctival sac two drops of a two per cent, solution of 
nitrate of silver, the lids having previously been wiped dry. 
Other materials recommended are aqua chlorini (Schmidt-Pim- 
pler), bichloride of mercury (1 : 5000), carbolic acid (1 per cent.), 
and nitrate of silver (1 : 500). The hands of the mother, nurse, 
and child should be searched for sources of infection, and, if 
gonorrhoea is known to exist in the mother, the child should 
be isolated. 

Treatment. — If the type is mild, the applications described 
under simple conjunctivitis are indicated ; if severe, three condi- 
tions demand attention : The inflammatory swelling of the lids, 
the state of the conjunctiva, and the corneal complications. 

(1) During the earlier stages, when the lids are tense and the 
secretion lacking in its later creamy character, in addition to abso- 
lute cleanliness, local applieation of cold is the most useful agent. 

This should be applied in the following manner : Upon a 



DISEASES OF THE CONJUNCTIVA. 225 

block of ice, square compresses of patent lint are laid, which, in 
turn, are placed upon the swollen lids and as frequently changed 
;i> may be needful to keep up a uniform cold impression. This 
is far preferable to the use of small bladders containing crushed 
ice ; indeed, the use of ice for infants is not advisable. The 
length of time occupied with these cold applications must vary 
according to the severity of the case. Sometimes they may be 
used almost continuously, and sometimes frequently for periods 
of half an hour at a time. 

On the other hand, hot fomentations are occasionally better 
than cold, especially when corneal complications exist, or the 
surface of the conjunctiva is covered with a gray film. These 
are applied with squares of antiseptic gauze wrung out in carbo- 
lized water of a temperature of 120° F., and frequently changed. 

(2.) Constant removal of the discharge must be practised. 

The lids are to be gently separated, the tenacious secretion 
wiped away with bits of moistened lint or absorbent cotton, and 
the conjunctival sac freely irrigated with an antiseptic fluid. 
For this purpose a saturated solution of boric acid (which is 
feebly antiseptic, but very cleansing and slightly astringent), or 
one of corrosive sublimate, a grain to a pint (strong solutions 
should not be used, because they may injure the corneal epi- 
thelium and cause ulceration), may be employed. Special and 
ingenious forms of lid irrigators have been devised. The cleansing 
process must be repeated at least every hour, day and night, and, 
if necessary, much more frequently. 

The remedies mentioned on page 219 have found favor with 
some surgeons. In addition to these may be mentioned carbolic 
acid (one-half to five per cent.), nitrate of silver (one to two per 
cent.), alcohol and bichloride of mercury solutions, iodoform oint- 
ment (four per cent.), aqua chlorini, cyanuret of mercury (1 : 1 500), 
permanganate of potassium (1 : 1000), employed in copious irriga- 
tions, and formol (1 : 2000). Peroxide of hydrogen acts efficiently 
in cleansing away the purulent secretion, care being taken that it 
contains as little free acid as possible. The author has usually 
secured the best results with boric acid or weak solutions of mer- 
curic chloride. The frequent insertion of vaseline beneath the 
lids is highly commended and should always be practised. 
15 



226 DISEASES OF THE EYE. 

(3.) The local application of nitrate of silver to the conjunctiva 
must not be made in the earlier stages before free discharge is 
established, nor in those cases, no matter what the stage, when 
the lids are tense and board-like, and the surface of the conjunc- 
tiva covered with a gray film, or a false membrane. 

When the secretion is free and creamy, when the lids are re- 
laxed, when the conjunctiva is dark-red and puckered into papilla- 
like excrescences, the time for its application has come. Once 
a day the palpebral conjunctiva and retrotarsal folds should be 
brushed over with a solution, ten or twenty grains to the ounce, 
its surface first having been carefully freed from any adherent 
discharge, and afterwards all excess of the drug washed away 
with a solution of common salt and this washing continued until 
a clean red surface is secured, when the lids may be returned to 
their proper position, their margins greased with vaseline and 
some of the lubricant introduced within the conjunctival cul-de- 
sac. Ulceration of the cornea does not alter the treatment de- 
scribed, except that pressure upon the globe while manipulating 
the eye is to be avoided. So long as the discharge is abundant 
the use of the caustic is indicated. 1 

At the first appearance of corneal haze, a four-grain solution 
of atropine is to be dropped into the eye two or three times daily. 
If, however, a marginal ulcer forms, and danger of perforation 
is imminent, or even if this has occurred, good results are obtained 
with eserine. The use of eserine requires considerable care, lest 
any co-existing hyperemia of the iris be aggravated by the drug, 
and iritis ensue. For this reason many surgeons prefer not to 
employ it, although its great efficacy in preventing sloughing of 
the cornea cannot be denied. 

Persistent swelling of the conjunctiva is sometimes treated by 
scarification. Division of the outer commissure to relieve pressure, 
leeching, and, indeed, any form of treatment followed by decided 
loss of blood, are hardly suited to young infants, although they 
may be indicated in adults. 

If one eye alone is affected, suitable protection for the sound 

1 Nitrate of silver combines the properties of an astringent, superficial 
caustic, and germicide. 



DISEASES OF THK CONJUNCTIVA. 227 

eye should be provided. Thismay be accomplished by antiseptic 
bandaging of the uninflamed organ (Buller'a shield is difficult of 

application in infants). The daily use in the unaffected eye of a 
drop of a two per cent, solution of lunar caustic has been sug- 
gested. 

Reduction of the inflammation with cold applications, for 
which, under the conditions named, hot affusions are substituted; 
absolute cleanliness; frequent irrigation with antiseptic and 
slightly astringent solutions; and at the proper stage nitrate of 
silver, will meet with the best results. 

The attendants must be impressed with the fact that upon their 
faithful carrying out of directions and upon their unremitting 
care much, if not all. of the hope of bringing the case to a suc- 
cessful termination depends. The attendants must further be 
impressed with the contagious nature of the pus ; all bits of rag 
and pledgets of lint used in the treatment must be destroyed, and 
after each treatment the hands of those engaged must be thoroughly 
washed and then disinfected with a solution of bichloride of 
mercury. 

Gonorrhoeal Conjunctivitis (Purulent Ophthalmia; Acute 
Blennorrhcea in Adults) usually can be traced to its source of 
contagion from an acute gonorrhoea or a gleet, by contact with 
soiled fingers or linen, or from an eye similarly affected. 

Purulent conjunctivitis, not gonorrhoeal in origin, mav be caused 
by the secretion of diphtheritic conjunctivitis, and occasionally by 
granular lids. Vaginal leucorrhoea is not uncommon in young 
girls, and from this they may inoculate their eyes. It is to be 
remembered that a catarrhal conjunctivitis by neglect or injudi- 
cious external applications, like poultices, may be aggravated into 
au inflammation in all particulars resembling gonorrhoeal con- 
junctivitis. A few instances of purulent conjunctivitis are on 
record in which the source of contagion could not be fouud, and 
h'-nce the origin has seemed to be spontaneous. 

The same micro-organism described in connection with oph- 
thalmia neonatorum is active in gonorrhoeal conjunctivitis, the 
diplococci being found within the cells; later they penetrate the 
epithelium and enter the lymph spaces in the subconjunctival 
ti— ue. 



228 DISEASES OF THE EYE. 

Symptoms. — The first symptoms appear from twelve to forty- 
eight hours after inoculation, and resemble those already recited 
in connection with the same disease occurring in the newly born. 

The vitality of the cornea is in constant danger, and compli- 
cations in this membrane may arise during the height of the 
attack, or later, and when convalescence apparently is established. 
These consist either in ulcers, small or large, central or peripheral ; 
in the latter position they often exist as grooved rings or small 
clean cut lesions without infiltration, hidden by the swelling of the 
surrounding conjunctiva, and very prone to perforate. A more 
or less dense opacity may follow ulceration, or arise independently 
of this condition. 

If perforation occurs, all the phenomena described on page 
223 will ensue, and even without perforation, iritis, cyclitis, and 
disease of the deeper structures of the eye may develop and defeat 
the possibility of obtaining good vision. 

Gonorrheal conjunctivitis reaches its climax in about ten days, 
and then gradually subsides in from one to two months ; or it 
may pass into a chronic type and be one of the forms of chronic 
blennorrhea, which then consists of a general redness of the pal- 
pebral conjunctiva, with hypertrophy of its superficial layers and 
some thickening of the papilla?. 

Treatment. — This includes the same principles and practice 
described in connection with ophthalmia neonatorum (page 224), 
but requires certain modifications suggested by the adult age of 
the majority of the cases. 

Depletion. — In the beginning, when the inflammatory action is 
of high degree, a few leeches may be applied to the temple. If 
the swelling of the lids is so great that their pressure threatens 
to destroy the cornea, the outer canthus may be divided (cantho- 
tomy). .This acts in a twofold manner by relieving pressure 
and by depleting the engorgement through the loss of blood 
occasioned by the incision, which should be made with a scalpel 
cutting the tissues from without, down to the bone, as far as the 
margin of the orbit, but leaving the conjunctiva uninjured. 
Repeated incisions of the hard rim of chemotic conjunctiva 
which surrounds the cornea will also relieve pressure. In despe- 
rate cases, some operators (Critchett, Fuchs) have not hesitated 



DISEASES OF THE CONJUNCTIVA. 229 

to split the lid vertically and stitch the divided portions to the 
brow, restoring them by a plastic operation after the disease has 
subsided. 

Application of Gold and Heat. — Cold may be applied with 
compresses in the manner described, or continuously, with Leiter's 
tubes. Under the circumstances already mentioned, hot appli- 
cations should he substituted. 

Local Applications. — These include the antiseptic lotion.- pre- 
viously given (page 225), in addition to which may be mentioned 
a drug which has found favor with many, viz., permanganate of 
potassium. A solution (1 : 100) is prepared, from which a suf- 
ficient quantity is taken to alter one-half pint of water to a deep 
wine-color, and the lotion then used copiously, a pint at a time, 
in continuous irrigation. 

At the proper stage, nitrate of silver is the best remedy. It 
is rarely necessary to employ it in a strength greater than ten 
to fifteen grains to the ounce, but when the granulations of the 
conjunctiva become exuberant, the mitigated or solid stick at 
times alone will control the process. 

Corneal Complications. — On the appearance of any of the 
types of ulceration, the surgeon must decide between atropine 
and eserine. Xo question arises if the iris is inflamed, but in 
the absence of such complication the action of eserine is most 
favorable. The best results follow the use of eserine during the 
day (gr. ^— ^ : f sj), one drop every three or four hours, and a few 
drops of an atropine solution (gr. iv. :f.5J) at night. Instead of 
eserine, hydrochlorate of pilocarpine, in twice the strength, may 
be employed. Iodoform freely dusted upon the ulcer is of service, 
and other measures mentioned on page 271 must be considered. 
Aristol, which has been recommended as a substitute for iodoform, 
is of doubtful value. 

If an ulcer threatens to perforate, paracentesis (page 599) 
through its floor will diminish the intraocular pressure, and may 
prevent or lessen the extent of prolapse of the iris. A substitute 
for this operation is the use of the actual cautery. If perfora- 
tion has taken place, excision of the prolapsed iris, sometimes 
recommended, is not without danger, as this procedure may open 
a way for the entrance of infecting material to the deeper struc- 



230 DISEASES OF THE EYE. 

tares of the eye. Hence in a small prolapse, peripherally situ- 
ated, the vigorous application of eserine, or, in one centrally 
placed, the use of atropine, may secure better results. The final 
outcome of the case will depend upon the extent of corneal in- 
volvement, and the ultimate treatment of the remaining leucoma, 
staphyloma, or shrunken ball will require, according to circum- 
stances, iridectomy, abscission, evisceration, or enucleation. 

General Treatment. — If the subject of gonorrhceal conjunctivitis 
is a vigorous individual, it has been recommended on good au- 
thority to bring the constitution under the influence of mercury, 
preferably by inunctions, early in the disease when there is high- 
grade inflammatory swelling. 

More often the patients are debilitated, and supporting treat- 
ment is indicated, quinine, iron, strychnia, and milk-punch, the 
last especially if there is a tendency to sloughing of the cornea. 
Any evidences of poor circulation call for digitalis and mix 
vomica, and these drugs modify favorably the failing nutri- 
tion of the cornea. If there is constipation calomel should be 
given, and saline laxatives in the morning. The pain, which is 
often severe, may be allayed with morphia or opium ; indeed, the 
latter drug has a good influence on the sloughing process. It 
is a mistake, in the serious forms of this disease, to depend alone 
upon local measures. 

The treatment of a chronic conjunctivitis, the sequel of an acute 
attack, depends upon the degree of thickening in the mucous 
membrane, but is usually best managed by careful exposure of 
the thickened conjunctiva and applications of nitrate of silver, 
tannin and glycerin, and the occasional use of the alum or sul- 
phate of copper stick. As a collyrium, boric acid or bichloride 
of mercury may be used, or these substituted with sulphate of 
zinc or acetate of lead, provided there is no corneal ulceration. 

Prophylaxis. — Patients suffering from gonorrhoea should 
be warned not only of the great danger of infecting their own 
eyes, but the eyes of those around them. Inasmuch as a very 
minute quantity of urethral discharge, and even when this is the 
product of a chronic disease, gleet, for example, may produce acute 
conjunctivitis, these precautions become the more necessary. 

As usually one eye alone is affected it is a matter of great im- 



DISEASES OF THE CONJUNCTIVA. 231 

portance to secnre the other eye from contact with the secretions. 
This may be done by sealing it with an antiseptic bandage, the 
edges of which are made tight by fastening along them strips of 
ganze painted with flexible collodion, or by the application of 
Bnller's shield. The latter consists of a watch-glass fitted in a 
square piece of rubber adhesive plaster, which is carefully applied 
to the brow, temple, lower margin of the orbit and nose, and 
should be secured with additional strips to prevent the entrance 
of discharge. 1 The inner margin should be sealed with collodion, 
as contamination is most likely to occur at this point and inef- 
ficient application increases rather than diminishes the danger. 

Fig. 85. 




Application of Buller's shield. 

All the precautions which have been stated in regard to the 
care of conjunctivitis neonatorum apply with ecpual and even 
greater force in the present disease. The surgeon in attendance, 
in a number of instances, has been contaminated. 

Prognosis. — The prognosis is always grave, even more so 
than in conjunctivitis neonatorum. 

There is one form of conjunctivitis, occasionally seen during 
gonorrhoea, which does not depend upon the introduction into 
the eye of an infecting material from the urethra, but which 

1 Care should he taken to provide a watch-glass of the ordinary form, not 
one with a concave centre. 



232 DISEASES OF THE EYE. 

occurs in patients who at the same time have articular affec- 
tions. 

The disease is bilateral, mild in character, and resembles a 
moderate catarrhal conjunctivitis with some swelling of the mu- 
cous membrane. Iritis has occasionally followed this inflamma- 
tion, just as it is seen associated with gonorrheal rheumatism. 1 

The treatment of this affection calls for the same remedies useful 
in ordinary conjunctivitis. 

Croupous Conjunctivitis. — This is an inflammation of the 
conjunctiva characterized by a soft, usually painless swelling of the 
lids, a membranous exudation upon the conjunctiva, and a scanty 
sero-puruleut discharge. 

Causes. — The affection in its pure form is rare. It is never 
found among the new-born, and rarely among grown-up people, 
the majority of cases occurring between the first half year of life 
and the fourth year. 

The contagiousness of the disease has not been established ; no 
definite cause is known, although some relation exists between 
this disorder, scrofula, eczema, and the definite age of childhood 
just mentioned. Some authors regard it as a mild diphtheria. 
Patients affected may at the same time be suffering from a croup- 
ous inflammation of the respiratory tract. 

Symptoms. — These begin with an acute ophthalmia, succeeded 
by swelling of the lids, which remains soft and pliant and usually 
not painful to the touch. In a few days there is a deposit of a 
characteristic false membrane composed of coagulated fibrin, 
rather translucent and porcelain-like in appearance, beginning 
upon the retrotarsal folds, coating the inner surfaces of the lids, 
but not invading the bulbar conjunctiva. It may readily be re- 
moved and shows beneath a granular and somewhat bleeding 
surface. It is quickly reproduced. The cornea, except in severe 
cases, escapes. 

Healing takes place in from ten to thirty days except in those 
instances when the membrane is formed again and again, and the 
course of the disease may continue for months. 

1 Some surgeons apply the name " gonorrhoea! ophthalmia" to this affection, 
and reserve the term " gonorrheal conjunctivitis" for the disease which is caused 
by a specific urethral discharge. 



DISEASES OF THE CONJUNCTIVA. 233 

Diagnosis. — The disease may be confounded with conjuncti- 
vitis neonatorum and diphtheritic conjunctivitis. From the 
former it is distinguished by the absence of profuse purulenl dis- 
charge and the age of the patient ; from the latter, by the soft 
swelling of the lids, the superficial character of the membrane, 
ami absence of the Klebs-Loeffler bacillus. 

Treatment. — Uninterrupted application of ice compresses, 
frequent removal of the discharge with a solution of chloride of 
sodium or chlorate of potash, and later the cautious use of nitrate 
of silver. (Knapp.) Other applications recommended are dilute 
lead-water, chalk-water, iodoform and quinine. 

Diphtheritic Conjunctivitis. — This is characterized by a 
board-like, very painful swelling of the lids, a scanty sero-purulent 
or sanious discharge, and exudation (containing the Klebs-Loef- 
fler bacillus) within the layers of the tarsal conjunctiva, which 
spreads to the ocular conjunctiva, and by pressure destroys the 
nutrition of the cornea. 

Causes. — The disease, which is contagious, may originate from 
a similar case, or arise in the course of a purulent conjunctivitis. 
It has occurred, though rarely, with conjunctivitis neonatorum. 
At times it appears in connection with eczema of the face and 
borders of the lid, and is an occasional accompaniment of some 
acute illness, like scarlet fever or measles, when the diphtheritic 
type of the inflammation becomes engrafted upon the conjunctiva. 
The disease has been seen during epidemics of diphtheria, and 
may be part of a process which passes from the nose to the con- 
junctiva, or may be due to direct inoculation with the diphtheritic 
poison. 

It is commonest between the ages of two and eight, and is 
unusual in young infants. In certain localities in the south 
of France and the north of Germany the disease is frequent ; 
it is comparatively rare in America and England. 

Symptoms. — The patches appear in a discrete or confluent 
form ; the lids are swollen with a characteristic, painful, board- 
like hardness. The false membrane is of a dull, grayish appear- 
ance, and is torn off with difficulty. If the process is deep, the 
subjacent structure is pale, infiltrated, and when cut into may be 



231 DISEASES OF THE EYE. 

anaemic and lardaceous. If the diphtheritic inflammation has 
been engrafted upon a case of purulent conjunctivitis, the abun- 
dant secretion ceases, or becomes irritating and sanious. 

Sloughing of the cornea is almost inevitable in severe cases, 
and rapid destruction of this membrane may take place in 
twenty-four hours; even in mild cases ulcers may be expected. 

Restlessness, fever, alimentary derangements and nervous phe- 
nomena are usual constitutional disturbances. 

This disorder is distinguished from the previous disease by the 
characteristic board-like infiltration of the lids and the bacterio- 
logic examination, and has nothing in common with the flakes 
of false membrane sometimes seen in purulent conjunctivitis, 
from which it is further separated by the character of the dis- 
charge. 

Treatment. — During the earlier stages, cold compresses 
applied in the manner already described are of doubtful value, 
because, as corneal involvement is almost inevitable, hot affusions 
are more suitable. The eyes should be frequently cleansed with 
warm boric acid solution, and atropine drops instilled, which, if 
the ulceration of the cornea is peripheral, may be associated with 
eserine. Iodoform salve (or powder) should be freely applied 
within the conjunctival sac ; indeed, vaseline itself is efficient 
under these circumstances. Besides the collyria mentioned, solu- 
tions of salicylic acid or of carbolic acid in glycerin have found 
favor. Fieuzal advises lemon juice aud citric acid ointment. 
Solutions of quinine are recommended by Tweedy. 

Internally, the most useful remedies are quinine, iron, and 
mercury ; the first in suppositories, and the last either as calomel 
or as the bichloride, of which -fa to fa of a grain may be given 
hourly to a child from three to six years of age. Recent experi- 
ences indicate the great value of diphtheria-antitoxine. 

The sound eye should be guarded by a bandage, or by Buller's 
shield. Isolation of the case is necessary, especially if it is in the 
neighborhood of children who suffer from facial eczema or any 
form of catarrhal conjunctivitis. 

Many writers consider diphtheritic and croupous conjunctivitis 
as subdivisions or different grades of a single disease, known as 
plastic or membranous conjunctivitis. 



DISEASES OF THE CONJUNCTIVA. 235 

Phlyctenular Conjunctivitis {Phlyctenular Ophthalmia, 
Scrofulous Ophthalmia, Eczema of ike Conjunctiva). — This is a 
tonn of inflammation of the conjunctiva, characterized by the ap- 

pearance of one or more grayish elevations, situated chiefly upon 
it- bulbar portion in the immediate vicinity of the cornea. 

CAUSES. — The disease is believed to be of constitutional origin, 
and its subjects are often strumous and badly-nourished children. 
Errors of diet, unwholesome foods, and the use of tea and coffee 
act as predisposing causes. It often follows the exanthemata, 
especially measles. Rhinitis is always present. Micro-organisms 
have been described, but inoculations with them were negative. 

Symptoms. — The disease occurs in a single and multiple form ; 
the pimples or phlyctenule lie near the corneal margin or directly 
upon it, and are usually from 1 
to 3 mm. in diameter. 

If the elevations are large, 
yellow, and contain purulent ma- 
terial, the disease has been called 
pustular ophthalmia. 

Under any circumstances it is 
accompanied by pain, dread of 
light, injected bloodvessels, and 
increased lachrymation. The con- Phlyctenular conjunctivitis. 

, . , (Children's Hospital.) 

junctiva may be transparent, or 

the disorder associated with a muco-purulent conjunctivitis. 

After the exanthemata, this association is common. 

In the multiple form, numerous minute phlyctenule may be 
scattered over the entire conjunctiva, and are accompanied by 
decided general red injection, irritation, and photophobia. The 
disorder subsides in from ten days to two weeks. 

Treatment. — Locally, mild antiseptic collyria, especially a 
lotion of boric acid, are applicable. Much irritation calls for 
the use of atropine drops and the occasional instillation of 
cocaine to relieve the photophobia. The eyes may be protected 
by colored gla—< s. 

After the acute symptoms have subsided, the best results are 
obtained with the yellow oxide of mercury (gr. 1 to the 3j)> or 




236 DISEASES OF THE EYE. 

with calomel, provided the patient is not taking iodide of potas- 
sium, otherwise a reaction between the potassium iodide in the 
tears and the calomel occurs, with the ultimate formation of 
double iodides, which are caustics {calomel conjunctivitis). 

An excellent regulation treatment is a mild course of mercurial 
laxatives. Simple diet, good air, exercise, and internally quinine, 
iron, arsenic, and cod-liver oil, complete the therapeutic measures. 

Phlyctenular conjunctivitis is so closely allied to phlyctenular 
keratitis that the separation of the two affections is purely arti- 
ficial, and this account is a preface to the description of the more 
exact disposition and relation of the phlyctenule, which appears 
on page 259. 

Spring Conjunctivitis (Fruehjahr's Catarrh (Saemisch), 
Plilyctcena Pallida (Hirschberg). — This is a form of conjunctival 
disease, usually seen in children, and is characterized by photo- 
phobia, stinging pain, considerable mucous secretion, the forma- 
tion of flat grauulations in the conjunctiva, and an hypertrophy of 
this tissue surrounding the limbus of the cornea. 

Causes. — Definite information in regard to the cause of this 
peculiar disease does not exist. The characteristic behavior 
of the disorder has been stated to be its return in the early 
spring and its subsidence in the fall and winter, although cases 
are seen in other months of the year, and, moreover, spring and 
summer exacerbations of ordinary phlyctenular conjunctivitis are 
marked features. 

It is most frequent between the ages of five and fourteen, but 
occasionally occurs in advanced adult life. It may accompany 
the disease known as hay fever. Some writers decline to con- 
sider vernal conjunctivitis a distinct disease, but look upon it as 
a hypertrophic form of chronic conjunctivitis. 

Symptoms. — The affection begins like an ordinary conjunc- 
tivitis and is always bilateral. There are photophobia, more or 
less mucous secretion, circumscribed peri-corneal injection, and the 
formation in this region of small, gray, semi-transparent nodules, 
which swell up and overlap the edge of the cornea. 

Three varieties of the disease are described, the limbus, palpebral, 
and mired forms. The conjunctiva of the bulb is injected, that 
of the lids is slightly thickened, of a dull pale color, as if 



DISEASES OF THE <X)NJUNCTIVA. 237 

brushed over with a thin layer of milk (Horner). In severe 
cases, tin' tarsal conjunctiva is covered with flattened granula- 
tions, containing deep farrows between them. In the colored 
race, there is a brownish pigmentation of the scleral base of the 
hypertrophied masses (Burnett). 

The disease is t<> be distinguished from trachoma, by the flat- 
tened appearance of the granulations, and the absence of infiltra- 
tion and pannus. 

The prognosis of the disorder is not unfavorable, except in so 
far as relapses are concerned, which make its course a long one, 
often lasting from eight to ten years. Slight opacity of the 
cornea may result. 

Treatment.— During the height of the attack, the eyes may 
be protected with dark glasses ; weak astringent and antiseptic 
lotions are applicable. Calomel, yellow oxide of mercury, iodo- 
form ointment, boroglyceride, and strong solutions of bichloride 
of mercury are useful. 

The exceedingly troublesome nature of this affection and its 
constant tendency to recur, have led some surgeons to use the 
actual cautery to destroy the flattened granulations and hyper- 
trophied masses at the limbus of the cornea. Incision of the 
superficial vessels which run from the outer and inner commis- 
sure and empty into the swelling at the limbus, has been per- 
formed, and electrolysis has been employed. 

Follicular Conjunctivitis (Follicular ophthalmia, Conjuncti- 
vitis follicvlaria simph ./•. Irctehoma follieulare, Folliculosis). — This 
affection is characterized by the presence of small, pinkish prom- 
inences in the conjunctiva, for the most part in the retrotarsal 
folds, and usually arranged in parallel rows. 

CAUSES. — The disease arises under the influence of bad hy- 
gienic surroundings, especially in pauper schools (where it may 
appear as an aggravated epidemic), but it is frequently seen in 
mild form, especially among children during their school years. 

Much difference of opinion exists as to whether follicular con- 
junctivitis should be placed in a separate category from granular 
conjunctivitis, or whether it should be regarded as an early stage 
of the latter disease. Although transitional forms apparently 
exist, the evidence, clinically at least, warrants the belief that 



238 DISEASES OF THE EYE. 

many forms of this affection are distinct from granular lids. 
Bacteriologically, the two disorders are believed to be identical. 

Symptoms. — The children — for it mostly occurs in children 
and young people — complain of slight dread of light and ina- 
bility to continue at close work, and inspection reveals numerous 
round elevations in the conjunctiva, chiefly along the fornix, 
which are tumefied lymphatic follicles. These may not be evi- 
dent at first, if there is associated with the disorder a catarrhal 
condition of the conjunctiva. The color of the follicles varies 
from nearly white to a decided pink. After their disappearance 
the conjunctiva regains its natural state. 

The disorder is to be distinguished from granular lids, by ob- 
serving that the small bodies are neither so large as true granu- 
lations, nor so highly colored as hypertrophied papilla? ; that the 
mucous membrane is not affected more deeply than the lym- 
phatic follicles ; and that cicatricial changes are not present. 

The "prognosis is good in so far as the fate of the mucous mem- 
brane is concerned, but the disorder is troublesome and will often 
last for months, and under imperfect hygienic surroundings and 
in crowded asylums, may prove a stubborn endemic. 

Treatment. — Locally, boric acid, either alone or made up 
with a few minims of alcohol to one ounce of water, weak 
bichloride solutions, and occasional application of iodoform or 
aristol, or subnitrate of bismuth and calomel^ equal parts, are the 
best medicinal measures. A salve of one-half grain of sulphate 
of copper to the drachm of vaseline has been highly extolled. 

Refractive error, if it exists, should be corrected with appro- 
priate glasses, because ametropia aggravates the disorder. In 
stubborn cases, especially in asylums, expression of the swollen 
follicles with suitable forceps should be performed (see page 597). 
Granular Conjunctivitis {Granular ophthalmia, Trachoma, 
Egyptian ophthalmia, Military ophthalmia). — This is an inflam- 
mation of the conjunctiva in which the membrane loses its 
smooth surface, owing to the formation of rounded granulations, 
which, after absorption, leave cicatricial changes. It may be 
studied under two forms — acute granulations and chronic granu- 
lations. 



DISEASES OF THE CONJUNCTIVA. 239 

Causes. — Acute granulations may arise primarily under the 
influence of 1>;i<1 hygienic surroundings and develop in institu- 
tions where the inmates arc crowded together. The disease is 
propagated by the secretion of one eye coining in contact with 
another, and perhaps through the atmosphere, and is more likely 
to attack subjects whose nutrition has been enfeebled by scrofu- 
losis and tuberculosis, but it is not caused by these dyscrasias. 

Acute granulations, in the true sense of the term, is not a 
common disease in this region, and must not be confounded 
with the violent exacerbations to which the chronic forms of 
the malady are liable. 

Chronic granulations may result from the imperfect disappear- 
ance of the acute granulations, but much more frequently appear 
a- a primary disorder, and when no such ancestry can be traced. 
Certain individuals, especially of lymphatic constitution, are 
predisposed to chronic granular lids, and although its subjects are 
often pale and anaemic, because they live in badly ventilated 
homes, there is qo proven constitutional disorder which causes the 
disease, as it may attack those who are in perfect health. This 
predisposition is not confined to individuals, but includes races, 
the Jews, the Irish, and the inhabitants of the East, as well as 
the Indians in our country, being especially liable to the affec- 
tion, while the negroes are almost exempt. These facts have led 
a few observers to believe that there must exist in the form of a 
dyscrasia a predisposition to this disease (Burnett). 

The geographical distribution of trachoma has attracted much 
attention, and it has been found that the dwellers in certain re- 
gions of the earth, where the climate is damp, are readily affected, 
while an altitude of 1000 feet confers comparative immunity 
from the disease, and facilitates its cure. 1 

The dependence of granular lids upon a special micro-organism 
(the diploeoccus of Sattler, Michel, etc.) has not been established 
by inoculations, which were unsuccessful, except in half-starved 
animals (Staderini). Neither has the trachoma-coccus been iden- 
tified ; indeed, some observers (Mutermilch) deny its existence. 
A fungus, resembling microaporon furfur, active in rabbits, has 

1 According to Burnett, trachoma occurs at an altitude of 4700 feet. Van 
Millingeu denies the influence of altitude and an immunity for certain races. 



240 DISEASES OF THE EYE. 

been described by Noiszewski, and parasitic protozoa have been 
found by Pfeiffer and suspected by Ridley ; but the bacterial 
or protozoal origin of the disease has not been proven. Its 
contagious nature, however, is undoubted, especially when the 
eruption of the granulations is associated with free discharge. 
Transference of the morbid material to an eye, particularly if its 
conjunctiva is slightly inflamed, will result not only in a purulent 
conjunctivitis, but in a disease like the one from which it came. 
In this sense the secretion is specific. 

Nature of the Granulations. — The pathognomonic ap- 
pearance and essential element of the disease trachoma are the 
" granulations," ' but the life history and pathological histology 
of these bodies, and the identity or non-identity of folliculosis and 
granular lids, have not been entirely settled. 

Two views have been held — the one that they are new growths 
of special pathological character; the other that they are derived 
from the natural lymphatic follicles, and some authors declare 
that these follicles, and their changes, originate all the anatomical 
and clinical qualities of trachoma. 

A third view (Mutermilch) doubts the contagious and infectious 
nature of trachoma and asserts that any form of conjunctival 
inflammation may develop into granular disease. The follicles 
simply depend upon degrees of lymphoid infiltration, and the 
chief role is assigned to the epithelium. 

The following varieties of chronic trachoma have been recog- 
nized by systematic writers : — 

1. Papillary trachoma, in which the trachoma bodies or folli- 
cles are sparsely present and hidden from view by hypertrophied 
conjunctival papillae. This form is sometimes spoken of as chronic 
trachoma. 

2. Follicular trachoma, in which the presence of the " follicles" 
is the chief characteristic. Some authors consider follicular con- 
junctivitis (page 237) a variety of this type. 

In one type, designated by Knapp non-inflammatory follicular 
trachoma, the spawn-like granulations develop in the conjunctiva 

1 It should be remembered that the word "granulations" refers to the 
characteristic feature of trachoma, and not to surface granulations which 
may form during the course of the disease. 



DISEASES OF Mil". CONJUNCTIVA. 241 

without evidence of inflammation, and have been regarded as 
analogous to oaso-pharyngeal adenoid hypertrophies. 

o. Mixed trachoma, in which the follicles or bodies lie among 
hypertrophied and inflamed papillae, but are not hidden by them. 
This type is sometimes described as diflust or complicated trachoma. 

4. Sclerosing trachoma (Knapp), in which after an initial - _ 
rdinary granulations, leathery (fibrous), flattened excrescences 
develop in the upper tarsal and retrotarsal conjunctiva. 

:,. ' Cicatricial trachoma, in which atrophy and .sear tissue are 
manifest — "the end stage of uncured cases" (Knapp), 

Symptom? (Acute Granulations). — The lids are swollen, the 
conjunctiva reddened, and the papilla? hypertrophied, and between 
them are found the non-vascular, roundish "granulations." The 
dread of light i.- intense, and, on forcible separation of the lids, 
scalding tears gush out. The bulbar conjunctiva is injected, super- 
ficial vascularity of the cornea arises, and ulceration may appear. 

The patient complains of pain in the brow and temple. At 
first the discharge is scanty, but later muco-purulent or purulent. 

The process terminate- favorably or runs into the chronic form. 

[Oironic Granulations). — These often appear without antece- 
dent inflammation, and so insidiously that their real nature is for 
a time unknown to the patient. They usually develop first upon 
the lower lid, in the form of grayish-white, semi-transparent bodies, 
which vary in size according to their stage of development, and 
which, from fancied resemblances, have been called "sago-grain," 
or " vesicular" granulations. They may be disseminated or ar- 
ranged in parallel rows, and have sometime- been likened to the 
appearance of frog's spawn (follicular trachoma). The granula- 
tion- arc for the most part confined to the palpebral conjunctiva, 
and the upper retrotarsal fold (which is a favorite location) should 
be well exposed during the examination. Occasionally granula- 
tion- are found upon the caruncle and semilunar folds. 

The mucous membrane is pale or yellowish-red, unevenly 
rough, and contains the trachoma bodies, or follicles, which have 
a more or less deep situation and fill up the tissue. If they have 
not followed an acute process, there are few or no irritative man- 
ifestations and little discharge, perhaps only sufficient to glue 

_ ther the lids. As tim a - on the closely packed mass - 

16 



242 



DISEASES OF THE EYE. 



Fig. 87. 




compress the true conjunctival tissue and its circulation, and a 
superficial vascularity of the cornea may appear. This stage may 
last for months and be subject to numerous variations. 

In the next stage vascularity is increased, the follicles grow 
larger, soften, and their contents are forced out by the pressure 
of the surrounding infiltrations, forming, in association with the 

hypertrophied conjunctival pa- 
pilla?, red protuberances (mixed 
and papillary granulations). This 
period is associated with strong 
irritation and muco-purulent or 
purulent secretion, photophobia 
and symptoms of local pain, with 
fresh development of corneal 
complications. 

During the time of fatty de- 
generation and softening, which 
Follicular trachoma. (Johnson.) by some authorities is deemed a 

process of ulcerations, fresh follicular (granular) eruptions take 
place, in turn to go through the same changes which their forerun- 
ners have undergone. The mucous membrane now has a flesh- 
red appearance; it is with difficulty that the "granulations" are 
distinguished from the papillae, and indeed they are united with 
them, forming variously shaped diffuse or isolated protuberances. 

In the final stage cica- 
trization begins, and gray- 
white scar-lines appear, in- 
tersecting the remains of 
the old "granulations." 
When these cicatrices lie 
parallel to the ciliary bor- 
ders they present on ever- 
sion of the lid a typical 
appearance. 1 (Fig. 88.) 

By a gradual process 
of cicatrization of the old 
"granulations" and successive new crops, a chronic indu- 

1 It is convenient thus to divide the disease into three stages, as Eaehlinann 
has done, but it is not always possible to separate sharply each stage by symp- 
toms or appearances peculiar to itself. 




Typical granular lid and beginning cicatriza- 
tion, with pannus. I Berry. I 



DISEASES OF THE CONJUNCTIVA. 243 

ration and diffuse soar tissue results (cicatricial trachoma). This 
being firmly attached to the tarsus, which itself has undergone 
softening through a lymphoid infiltration, contracts, and the 
deformities of the lid and its border, so common in this disease, 
result. The fibroid induration of the mucous membrane affects 
all portions, and there may be almost entire obliteration of the 
conjunctival sulcus, or the membrane may undergo a species of 
drying up to which the name xerosis has been applied. Individ- 
uals with granular lids, in the stage of thickening of the mucous 
membrane, have an almost characteristic sleepy look, peering 
uncertainly through narrowed palpebral fissures, caused by the 
ptosis-like droop of their indurated eyelids. 

Sequelae of Granular Lids. — The most important results 
of long-standing granular lids are trichiasis, distichiasis, and en- 
tropion, conditions already described (page 209), atrophy and 
shrinking of the conjunctiva from cicatricial changes (page 249), 
cloudiness and ulceration of the cornea, and pannus. 

Pa an us may be looked upon as a form of vascular keratitis, 
which always begins under the upper lid, but which in severe 
cases may involve the entire cornea. It depends upon the for- 
mation of a superficial bloodvessel tissue, continuous with the 
vessels of the conjunctiva. It may be composed of only a few 
vessels (pannus tenuis), or be thick, fleshy (pannus crassus), and 
bulging in appearance. Unless softening and ulceration occur, 
which is not infrequently the case, the true corneal tissue is not 
much affected. 

It is usually taught that pannus is mechanical in origin and is 
caused by the friction of the granulations. According to Raehl- 
mann, however, it should not be considered as a simple traumatic 
irritation, but as a follicular process, with the formation of 
lymphoid infiltration, analogous to the same pathological con- 
dition in the conjunctiva ; in short, pannus is to be regarded as a 
special implantation of the trachoma process in the layers of the 
cornea. Mutermilch believes that pannus does not depend upon 
roughness of the conjunctiva, but upon the destruction of living 
epithelium, and when this is regenerated the pannus subsides. 
Extensive and deep ulceration may complicate pannus, which in 



244 DISEASES OF THE EYE. 

turn may lead to the development of iritis; or the cornea may- 
become entirely opaque ; or finally the ulceration maybe followed 
by perforation of this membrane and staphylomatous bulging. 

Diagnosis. — This presents no difficulties. Acute granulations 
must be distinguished from purulent conjunctivitis, but the chronic 
form is made evident by direct inspection of the everted lids, 
unless the associated swelling of the papillae is so great as to 
obscure the " granulations," especially in the forms of papillary 
trachoma. Hypertrophied conjunctival papillae, chronic blennor- 
rhea, or surface granulations must not be mistaken for trachoma. 
The clinical distinctions existing between trachoma and follicular 
conjunctivitis have been pointed out. 

Prognosis. — Under the best circumstances, granular lids 
when well established is a tedious disease, and greatly endangers 
the vision of the patient. Relapses are frequent, and at any 
time the disorder is likely to assume an intense inflammatory 
action analogous to acute granulations. Its contagious character 
renders the affection especially dangerous in schools or any insti- 
tution where large numbers of inmates are gathered together. 
The discharge, even when present in slight degree, is readily 
conveyed from one subject to another by the careless use of 
towels and common utensils. Great caution is necessary under 
such circumstances to prevent a disastrous epidemic. 

Treatment. — Acute Granulations. — These are managed upon 
the principles which govern the treatment of acute conjunctivitis 
generally, and in the earlier stages require soothing remedies 
rather than strong astringents. 

Chronic GraniUations. — The treatment of chronic granular 
lids may be divided into three methods: Application of caustics 
and astringents, operative procedures, and general medication. 

Local applications include the astringent and caustic prepara- 
tions which are used to cause absorption of the "granulations," 
but these should not be of such strength that they will produce 
cicatricial changes more harmful than the original malady. A 
variety of substances has been employed, and among them four 
have met with deserved favor — strong solutions of bichloride of 
mercury; nitrate of silver; sulphate of copper, either in the form 
of a crystal, or as lapis divinus; and boroglyceride. 



DISEASES OF THE CONJUNCTIVA. 245 

During the stage of conspicuous lymphoid infiltration and de- 
cided follicular ("granular") eruption, without the presence of 
purulent discharge, bichloride of mercury, 1-300 or 1-500, may 
be applied to the everted lids, with an absorbent cotton-mop, from 
Once a day to thrice weekly, according to the amount of reaction 
produced, the conjunctival cul-de-sac being frequently irrigated 
during the day with a tepid solution of the same drug (1-8000). 

In the stage of softening of the granulations and swelling of the 
conjunctival papillae, associated with muco-purulent and purulent 
discharge, nitrate of silver, applied in the same manner and with 
the same precautions that have been described under Purulent 
Conjunctivitis, is the best remedy. 

During the same stage in which strong solutions of bichloride 
of mercury have been recommended, or, as it seems to the author, 
more properly at a somewhat later period, when eruption of new 
granulations is associated with beginning cicatricial metamorphosis 
of old crops and their surrounding tissue, but when there is no 
purulent discharge, sulphate of copper crystal is a standard rem- 
edy, and is the one usually recommended for routine treatment. 
The crystal should be smooth and carefully applied to all portions 
of the affected areas, especially to the retrotarsal folds, and the 
treatment followed by washing the surface with cold water. It 
is a painful remedy, and in sensitive patients, there is no objec- 
tion to cocainizing the eye preparatory to its use. 

During the later stages, to hasten absorption of remaining 
granulations, and, perhaps, to prevent the tendency to xerosis, 
boroglyceride (30-50 per cent.) is a useful remedy, applied in 
the usual manner with a mop of cotton. Some surgeons employ 
this drug in all stages of the disorder. 

Among the many remedies which have been tried in this 
affection, the following may be mentioned : Liquid carbolic 
acid, liquor potassa, betanaphthol, hydrastin, iodoform or aristol 
(in powder or salve), an ointment of the yellow oxide of mercury, 
calomel, and iodide of silver. In mild cases, or after an impres- 
sion has been made with stronger caustics, a favorite astringent 
is tannin and glycerine (30-60 grains to the ounce), or the everted 
lids may be touched with an alum crystal. 

During the course of the treatment, the affected areas should be 



24G DISEASES OF THE EYE. 

frequently irrigated with saturated boric acid or weak bichloride 
of mercury solutions; if much discharge is present, this is impera- 
tive. At any time granular lids are liable to take on acute symp- 
toms : increased discharge ; exacerbation of pannus, with clouding 
and ulceration of the cornea; hyperemia of the iris; and acute 
pain in the brow and temple. Usually, strong local applications 
must then be discontinued, and the treatment instituted which 
is applicable to an acute conjunctivitis. Cold compresses, more 
suitably substituted by hot applications if there is much corneal 
disease, frequent cleansing with tepid boric acid lotion, leeches 
to the temple, and atropine to keep the pupil dilated, unless this 
drug itself should aggravate the granular condition, when it may 
be replaced by hyoscyamine, are then indicated. 

Operative Procedures. — This includes the various methods for 
removing the granulations by scarification of the conjunctiva ; 
abscission of the granulations ; excision of the retrotarsal fold ; 
destroying them, when discrete, by picking them out one by one 
with a fine needle and emptying their contents, or burning them 
with a heated wire or galvano-cautery ; and squeezing them out 
between the thumb-nails, or with specially devised forceps, the 
two most satisfactory instruments for this purpose being the 
model of Xoyes, and the forceps, on the principle of a roller, 
advocated by Knapp. Exuberant granulations have been scraped 
away with a small rake or a sharp curette ; or removed by rub- 
bing them briskly with a stiff brush, and then applying strong 
solutions of bichloride of mercury (" grattage?'). 

Great care must be exercised in practising any of these methods, 
lest the scar resulting from the operation, produce deformities in 
the lid greater than those likely to be occasioned by the disease ; 
hence if the hot needle or galvano-cautery is used, the isolated 
trachoma bodies alone must be attacked, and the surrounding 
conjunctiva carefully excluded. Of the methods just enume- 
rated, squeezing out of the granulations with forceps is the most 
satisfactory. 1 During its performance, the area of operation 
should be flooded with tepid bichloride collyrium, and cold com- 
presses afterwards applied to subdue inflammatory reaction. 

1 The squeezing operation is more suited to the follicular forms of trachoma 
than to the other varieties. 



DISEASES OF THE CONJUNCTIVA. 247 

Finally mention may be made of the method by electrolysis re- 
cently advocated by Mr. George Lindsay Johnson. 

Treatment of Pannus. — If this is limited in degree, it requires 
no special treatment as it -will disappear with the absorption of 
the granulations. But if it is extensive, and especially if asso- 
ciated with ulceration, special treatment should be directed 
towards its cure. This includes the local remedies which are 
appropriate for a vascular keratitis, viz., an antiseptic lotion, and 
atropine, or eserine, or pilocarpine. The first should be used 
if any tendency to iritis exists, and if it does not aggravate the 
granular condition; the last, when ulcers are present. It is 
suitably reinforced by the use of atropine at night. 

Inveterate pannus without ulceration of the cornea at one time 
was treated by the production of a violent conjunctivitis, charac- 
terized by the formation of a somewhat clinging false membrane, 
with a 3 per cent, infusion of jequirity painted upon the everted 
lids. This method was introduced by De Wecker to substitute 
the old-fashioned inoculation of the conjunctiva with blennor- 
rhceic pus. It has also been advised to apply the same drug in 
fine powder, a little at a time, exactly upon the portion of the 
granulations to be absorbed. The author doubts the propriety 
of its use under any circumstances. 

The operation of peritomy, which consists of an excision of a 
ring of conjunctival tissue surrounding the cornea, has been much 
practised for the relief of severe pannus. Another method is to 
scrape away the opaque and vascular areas in the cornea with a 
small knife (Gruening). If the palpebral fissure becomes con- 
tracted by cicatricial changes, or if during inflammatory periods 
in trachoma, the lids dangerously compress the cornea, the opera- 
tion of canthoplasty affords relief. 

General Medication. — It is a mistake to depend solely upon 
local measures for the relief of granular conjunctivitis, for 
although the disease has no proven constitutional origin, its 
subjects give frequent evidence of malnutrition, and are some- 
times affected with the scrofulous or tuberculous dyscrasia. 
Hence, in addition to every advantage that fresh air — if pos- 
sible, at a high elevation — good food, and pleasant hygienic 
surroundings can give them, iron, cod-liver oil, hypophosphite 



248 DISEASES OF THE EYE. 

of lime, arsenic, and, in short, a general tonic regimen should 
be exhibited. Suitable attention to the alimentary tract is im- 
portant. 

Chronic Conjunctivitis (Chronic ophthalmia), the result of 
an acute blennorrhoea, has been referred to on page 228. It 
may be associated with psoriasis (Hutchinson). 

As an independent disorder, and assuming more the type of a 
hyperemia, it is a common disease in elderly people. There are 
hyperaemia, thickening of the papillary layer of the tarsal con- 
junctiva, swelling of the caruncle, soreness of the edges of the 
lids, and slight muco-purulent discharge. 

Treatment. — Cleanliness, with antiseptic lotions, the appli- 
cation of " lapis divinus," the alum crystal, or glycerole of tan- 
nin (gr. x-f.y), are useful local measures. The puncta lachry- 
malia should be examined, and if they are closed they should be 
dilated and the lachrymal passages irrigated with an Anel syringe, 
and the nasal chambers should be carefully treated. Refractive 
error, which may keep up congestion, requires correction. 

Egyptian and Military Conjunctivitis are terms which 
have at different times been loosely used to describe all forms 
of conjunctival inflammations, occurring in crowded barracks 
and similar institutions, which assumed an epidemic tendency, 
pursued a more or less chronic course, and hence included vari- 
eties of acute and chronic blennorrhoea and muco-purulent 
conjunctivitis, in addition to those cases which possessed as a 
fundamental diagnostic symptom, "granulations" of the con- 
junctiva, and which eventuated in the formation of cicatrices. 

Lachrymal Conjunctivitis is really a form of chronic conjunc- 
tivitis depending upon obstruction of the lachrymal passages, and 
the frequently associated blepharitis. The eyelids are inflamed 
upon their borders, the cilia gathered in little tufts by the forma- 
tion of small pustules at their bases, the conjunctiva is injected 
and tear-soaked, and there is a somewhat gummy discharge. 

The treatment requires that the lachrymal passages shall be 
rendered patulous, in addition to the ordinary remedies suitable 
for chronic ophthalmia and ulcerated blepharitis. 

Lithiasis Conjunctivae is a troublesome condition caused by a 
calcareous degeneration of the secretion at the mouths of the 



DISEASES OF THE CONJUNCTIVA. 249 

Meibomian ducts. It is more commonly seen in elderly people 
than in young subjects, especially in such as arc rheumatic. On 
everting the litis, numerous small, yellowish-white concretions 
will be seen, distinctly gritty to the touch. These act like so 
many foreign bodies, and produce considerable irritation and pain. 

Each concretion should be removed with a fine needle, the 
conjunctiva having first been rendered insensitive with cocaine. 

Toxic Conjunctivitis is a name suited to those forms of con- 
junctival inflammation caused by exposure to the influence of 
certain chemicals, or by the prolouged use of the mydriatics 
(notably atropine) and the myotics. 

Atropine Conjunctivitis occurs at all ages, but is commonest in 
old people. Sometimes it will appear after only a few drops of 
the solution have been used, but usually not until the drug has 
been employed for a long time. Attempts have been made to 
explain it by assuming impurities in the drug, the existence of 
free acid, a septic origin owing to the presence of a fungoid 
growth, and idiosyncrasy. In a number of instances arthritic 
history has been obtained (Collins). The disease usually appears 
in the form of follicular granulations, sometimes associated with 
much swelling of the lid, and eczema of the surrounding tissue. 

Eserine, hyoscyamine, duboisine, and homatropine less com- 
monly cause this affection, and the same disorder has been re- 
ported as the result of the prolonged use of cocaine. 

Conjunctivitis occurs among those who work in aniline dyes, 
and from chrysophanic acid, when this has been used as an oint- 
ment in skin affections. It may follow the sting of flies (Berry), 
or irritation of caterpillar hair ("ophthalmia nodosa"). 

The treatment in general demands the removal of the cause, 
and in atropine conjunctivitis, applications of tannin and glycer- 
ine and of the alum crystal are very useful. In some instances 
the author has found a 1 per cent, solution of creolin of service. 
A bland ointment for the irritated cutaneous surface is indicated. 

Xerophthalmos (Atrophy of the Conjunctiva ; Xerosis) is the 
name employed by systematic writers to describe a dry, lustre- 
less and shrunken appearance of the conjunctiva, and is recog- 
nized under two forms — parenchymatous and epithelial. 

The former type results from cicatricial changes which involve 



250 DISEASES OF THE EYE. 

the deep layers of the conjunctiva ; the sulcus is obliterated, and 
the lids, in severe cases, are attached to the eyeball, while the 
cornea is opaque. The surface of the conjunctiva of the lids is 
smooth, dry, and almost leathery to the touch. Granular lids, 
diphtheritic conjunctivitis, pemphigus, and essential shrinking 
of the conjunctiva are the causes of the disorder. 

Treatment is of no avail, but some comfort may ensue by 
instilling glycerine and water, or by the local use of an emulsion 
of cod -liver oil. 

In the epithelial type the exposed ocular conjunctiva becomes 
dry and has a lack-lustre appearance ; cheesy flakes form, and 
the membrane is greasy and thrown into folds. This form of 
xerosis sometimes occurs in epidemics, associated with night- 
blindness, and is seen among people of poor nutrition — for in- 
stance, during prolonged fasts — or among soldiers whose eyes 
have long been exposed to sunlight. It is also one of the symp- 
toms of kerato-malacia in infants. (See page 279.) 

The treatment demands a nutritious diet, a soothing eollyrium, 
dark glasses, and removal from the surroundings which have 
caused the difficulty. 

Amyloid Disease of the Conjunctiva is a rare disorder, in 
which pale, yellowish masses appear chiefly in its palpebral por- 
tion. It has been supposed to arise from granular conjunctivitis, 
but, according to Raehlmann, the growths are independent of 
trachoma. 

Extirpation is the proper mode of treatment. Their structure 
is analogous to lymphoid tumors in which a hyaline degeneration 
may be found, and which in all probability is an antecedent con- 
dition. The diagnosis can be made with certainty only by sub- 
mitting the tissue to the iodine test. 

Pterygium is a peculiar fleshy growth, consisting of hypertro- 
phy of the conjunctiva and subconjunctival tissue. One or both 
eves may be affected. Its most usual situation is at the inner 
side of the eyeball, corresponding to the course of the internal rec- 
tus muscle; more rarely it develops at the outer, and very excep- 
tionally at the upper or lower part. "When the fan-shaped ex- 
pansion arises from the semi-lunar fold and caruncle, it converges 
as it approaches the cornea, the centre of which it rarely passes. 



DISEASES OF THE CONJUNCTIVA. 



251 




Large pseudo-pterygium, the result of a 
lime-burn. 



The growth is rare in young subjects and practically never 
occurs iu children, the average age, according to Fuchs, being 
about forty-eight, although it 

ft 1 ' 1 , 1 Fir;. 89. 

often develops at a much 

earlier period of life. The 
theory, advanced by Arlt, 
that ulceration at the margin 
of the cornea should be re- 
garded a-; the primary cause 
of the affection, is no longer 
tenable. According to Fuchs, 
pterygium is a development 
of a pinguecula, and like it, 
save in exceptional cases, be- 
longs to the so-called senile changes in the eye. As the pter- 
ygium develops, the characters of the pinguecula disappear. In- 
dividuals exposed to dust, smoke, wind, and heat are predisposed 
to the formation of pterygia. Pseudo-pterygia may result from 
blennorrhea, burns, or erosions of the corneal surface, the thick- 
ened conjunctiva becoming attached to the corneal lesiou. 

The treatment consists either in excision, transplantation, 
strangulation by means of ligatures, or evulsion (page 595). 

Pinguecula is a small, yellowish elevation situated in the 
conjunctiva near the margin of the cornea, and usually at the 
inner side. It has the appearance of fatty tissue, but is a hya- 
line degeneration of the connective-tissue fibres of the subcon- 
junctival tissue, and should be regarded, according to Fuchs, as 
the first stage in the development of a pterygium. It may be 
excised or destroyed with the actual cautery. 

Abscess of the Conjunctiva is a rare condition, in which a 
localized area of suppuration appears in the subconjunctival tis- 
sues. It may develop in children of greatly depressed nutri- 
tion, and has been the sequel of a wound. 

Ecchymosis of the Conjunctiva. — This is an extravasation of 
blood beneath the conjunctiva sclera?, the meshes of the connec- 
tive tissue being filled with blood-clot, and occurs as the result of 
an injury, or from some violent, straining effort, e. g., during a 
paroxysm of whooping-cough. It may arise without obvious 



252 DISEASES OF THE EYE. 

cause, especially in elderly people, and has been seen in young 
girls at the time of the menstrual epoch. It may indicate 
nephritis. Its occurrence during severe conjunctival inflamma- 
tions has been described. Ordinarily, subconjunctival hemor- 
rhage will subside by absorption, and requires no treatment. 

Chemosis {(Edema) of the Conjunctiva occurs when the con- 
nective-tissue layer is distended with sernm, and is often associ- 
ated with an inflammatory exudate. It is generally a symptom 
of some other disease — for example, acute conjunctivitis, choroid- 
itis, iritis, or orbital cellulitis. Severe oedema of the conjunctiva, 
with swelling and hyperemia, may appear without any apparent 
cause, and with marked suddenness. In paralysis of the exter- 
nal straight muscles the overlying conjunctiva is often decidedly 
cedematous, and may be an early symptom of such an accident. 
Chemosis of the conjunctiva following the use of iodide of potash 
has been reported by the author, and it may succeed a general 
outbreak of urticaria. 

Treatment. — The swollen tissues may be incised, and an 
astringent lotion, like alum, prescribed. 

Emphysema of the Conjunctiva consists in a distension of the 
connective-tissue spaces with air, and occurs under the same cir- 
cumstances which occasion this accident when it involves the 
eyelids. 

Lymphangiectasis of the Conjunctiva is a development of 
small blisters in the conjunctiva, filled with semi-transparent 
fluid, and usually gathered together in masses. These are situ- 
ated superficially, and readily move with the conjunctiva over 
the subjacent tissue. An interference with the natural lymph flow 
and consequent distension of the lymph spaces is the probable 
explanation of their appearance. The affection is said to be most 
frequent in children, but may occur at any age. Spontaneous 
disappearance is the common outcome, but, if need be, the small 
blisters may be incised. 

Syphilis of the Conjunctiva. — Chancres may develop on the 
upper or lower cul-de-sac, and even upon the ocular conjunctiva, 
as primary affections, and not only as extensions from the lids. 
A few instances of soft chancre have been described. 

As manifestations of general syphilis, ulcerated papular syphi- 



DISEASES OF THE CONJUNCTIVA. 253 

lids and gumma of the conjunctiva have been recorded. Finally, 
there is a type of inflammation called syphilitic conjunctivitis, which 
appears as a stubborn catarrh, or in the form of granulations, 
similar to trachoma follicles, developed in an anaemic and rather 
colloid-looking conjunctiva. Its subjects have been cases of pro- 
nounced syphilis, and the disease is not amenable to local treat- 
ment, but disappears under anti-syphilitic remedies. 

Tumors and Cysts of the Conjunctiva. — As congenital forms, 
translucent cysts, angiomas, lymph-angiomas, dermoid growths 
| s< m ■ page 298 ), and pigment spots have been described. Although 
tin' latter may be congenital, they may also appear after the heal- 
ing of variolous pustules. Nsevus of the plica has been reported 
by Snell. 

The cysts are not common. Sometimes several are seen in 
the region of the retrotarsal folds as small, oval, perfectly clear 
bodies causing no irritation, or as spherical growths upon the 
bulbar conjunctiva. 

Among the benign tumors, lipoma, fibroma, osteoma, and 
papilloma have their habitat upon the conjunctiva. Lipomas 
and lipomatous dermoids are found (Fig. 90) between the supe- 
rior and the external rectus. Papillomas have been confounded 
with bunches of granulation-tissue arising from wounds, e.g. after 
strabismus operations. Cydicerci, when they occur, are movable 
under the conjunctiva, have moderately thick and vascular walls, 
upon which an opaque white spot is seen, indicating the presence 
of the receptaculum. 

Treatment. — Excision with scissors curved upon the flat 
is readily performed in most of these instances. The wound 
may be united with fine sutures. In simple cysts, cutting away 
the anterior wall is usually sufficient to cause a cure. Xsevi 
have been treated with applications of ethylate of sodium (Snell). 

The malignant growths include epithelioma and sarcoma. 

epithelioma may occur as a primary growth upon the ocular 
conjunctiva, especially at the limbus cornese. In the latter situa- 
tion it appears as a reddish elevation, surrounded by injection. 
Finally, there are ulceration and implication of the cornea. 

The growths arc stated to be non-pigmented, but a number of 
pigmented or melanotic tumors have been removed from this 



254 



DISEASES OF THE EYE. 



region, which proved to be of epithelial structure. In a large 
collection of cases, Noyes has described other tumors found in 
this situation, not conforming to the type of epithelioma, but in- 
cluded under the general term carcinoma. 

Sarcoma of the conjunctiva arises at the limbus, in the form of 
a reddish-white growth, usually overlapping the cornea, but not 
involving its structure. Both pigmented and unpigmented varie- 
ties occur, the former being the more frequent. They may grow 
rapidly and reach a large size. 



Fig. 90. 



Fig. 91. 





Lipomatous dermoid of the conjunctiva: Sarcoma of the conjunctiva. (From B 
eye turned up and in. patient in the Philadelphia Hospital. I 

Removal of these growths by means of knife or scissors is 
practicable in the early stages, without sacrificing the eyeball. 
In the later stages, or when the extirpation cannot be made 
complete, enucleation is necessary. 

Lepra. — According to Lopez, the chief alterations in the 
conjunctiva produced by leprosy are anaesthesia, inflammation, 
pterygia, and tubercles. The anaesthesia of the cornea probably 
determines the chronic conjunctivitis which is common. Pterygia 
are frequently observed, and are caused by the action of external 
irritants upon the ocular conjunctiva which has become insensi- 
tive under the influence of the disease. 

It is convenient in this place to refer to the effect of leprosy 
upon the cornea, in which the lesions are frequent and varied. 



DISKA.-KS OF T1IK < < >N.I INrTI VA. 255 

The tubercles which form in the conjunctiva arc apt to attack 
the coraeo-scleral margin, but may involve the cornea exclu- 
sively. -V late manifestation of the disease is an inflammation 

of the cornea known as leprous keratitis, which somewhat re- 
sembles interstitial keratitis. 

Lupus occur- as a primary disease, or extends to the conjunc- 
tiva from the surrounding integument. It appears in the form of 
red, granular patches placed upon an ulcerated base. As the same 
microbe is the cause of lupus and tuberculosis, any difference 
existing in the two diseases when occurring in this situation, 
must rest upon the clinical appearances, the lupus spot showing 
healing in one direction and active ulceration in another. Those 
cases in which the disease has spread from the lid to the conjunc- 
tiva have especially been classified as lupus. 

Tubercle of the Conjunctiva occurs as a primary and as a 
secondary affection. 

Primary tuberculosis of the conjunctiva is rare, but a certain 
number of undoubted instances are upon record in which there 
was an absence of evidence of tuberculosis elsewhere, and in 
which there was no reappearance of the disease locally, or in dis- 
tant organs, after its removal. 

As a secondary affection it has usually appeared in association 
with nasal and laryngeal tuberculosis. 

The chief symptoms are a somewhat resisting thickening of the 
lids ; dark-red swelling of the conjunctiva, especially of the re- 
trotarsal fold, which is beset with grayish-red nodules resembling 
the follicles in grauular conjunctivitis ; and ulcers with uneven and 
slightly raised edges, whose floors have a lardaceous appearance, 
or are covered with grayish nodules, slightly sloughing in their 
apices. There is considerable discharge, and occasionally swell- 
ing of the tear-sac. The pre-auricular and submaxillary lymph- 
atic glands of the same side are enlarged. Pain is not consider- 
able unless the ulceration involves the bulbar conjunctiva and 
cornea, or extends to the lids. 

The di-« ase should lie distinguished from trachoma, epithelioma, 
and syphilitic ulceration. 

DIAGNOSIS. — In any suspected case, the real nature of the 
affection may be decided at once by excising a portion of the 



256 DISEASES OF THE EYE. 

diseased tissue, submitting it to bacteriological examination, and 
demonstrating the presence of tubercle bacilli. 

In trachoma the lymph-glands are not involved, and the fol- 
licles in acute cases will yield to treatment with sulphate of cop- 
per, while in tuberculosis this is ineffectual (Knapp). In the 
stages of the follicular formation of this disease, the discovery 
of the bacilli is the only positive differential diagnostic point. 

Epithelioma is excluded by the age of the subjects, tubercu- 
losis almost invariably occurring in young people. 

Prognosis. — This depends upon whether the disease is pri- 
mary or secondary. In order to prevent general infection, it is 
important to eradicate the local lesion. Sight may be destroyed 
by involvement of the cornea. 

The treatment demands destruction of all the diseased tissue. 
This is best accomplished by removal with a knife, curette, or the 
galvano-cautery. The subsequent treatment should include the 
use of a collyrium of bichloride of mercury, and iodoform or 
aristol powder. Injections of modified tuberculin, used in the 
manner in which this agent is employed in local chronic tubercu- 
losis (lupus), have been suggested. It seems a doubtful expedient 
not only as a curative, but also as a diagnostic agent. 

Pemphigus of the Conjunctiva is a rare affection, characterized 
by the formation of bullae, associated with pain and lachrymation, 
and, after succeeding attacks, degeneration and cicatrization of the 
conjunctiva. It is doubtful whether this occurs as an independent 
disorder ; it is usually seen in connection with pemphigus of the 
'rest of the body. 

The course of the disease, which tends to recur from time to 
time, is destructive to the nutrition of the conjunctiva, and later 
to the cornea. The former undergoes cicatricial change, and may 
grow fast to the ball ; the latter becomes opaque and staphylo- 
matous. 

Under the name Essential Shrinking of the Conjunctiva, a con- 
dition of atrophy, contraction and gradual disappearance of the 
conjunctival cul-de-sac has been described, during which the free 
borders of the lids become fixed to the ball and the cornea be- 
comes dry and opaque. This probably is a form of pemphigus, 
but has also been recorded as an essentially distinct process. 



DISEASES OF THE CONJUNCTIVA. 257 

These appearances must not be mistaken for granular lids, 

with which they have no association. 

Treatment. — It has been attempted to keep the conjunctiva 
moist with glycerine, and rabbit's conjunctiva has been trans- 
planted, but without results. 

Injuries of the Conjunctiva — (a) Foreign Bodies. — A small 
particle of coal, ash, or dust is easily removed, if lodged upon 
the lower portion of the conjunctiva; but if it finds its way be- 
neath the upper lid, and is situated far back under the retrotarsal 
fold, it may not come into view when the lid is everted, unless 
the fold is pushed into prominence. If the foreign body is at- 
tached to the tissues, it may be necessary to dislodge it with the 
point of a needle, or with a spud. Cocaine will render this 
operation painless. 

(b) Wounds. — These may be part of a serious injury involving 
the lid or deeper structures of the eye ; more rarely, they occur 
as simple lacerations, confined usually to the bulbar portion. In 
suitable cases, after proper cleansing, the lips of the wound should 
be drawn together with a few sutures. 

(c) Burns. — These are commonly inflicted with acids or un- 
slaked lime, and are especially serious because of the deformity 
which the subsequent contraction is likely to produce, or on ac- 
count of the development of a symblepharon (page 207). 

If the substance is lime, all the particles must be removed at 
once, and this is best accomplished by flooding the eye with 
water from a spigot ; if an acid, this may be neuti*alized with a 
weak alkali. The subsequent treatment calls for the instillation 
of olive or castor oil, and atropine drops, to prevent secondary 
iritis if the cornea is much inflamed ; the latter drug may be in- 
corporated with liquid vaseline and placed in the cul-de-sac. 

Affections of the Caruncle. — The caruncle and semilunar fold 
may be swollen in conjunction with a general inflammation of 
the conjunctiva, but also may undergo localized enlargement and 
inflammation, to which the name eneanthis has been applied, and 
which is subdivided by systematic writers into an acute, or in- 
flammatory, and a chronic variety. The process may go on to 
the formation of a minute abscess. 

Swollen caruncles are commonly found in patients with eye- 
17 



258 DISEASES OF THE EYE. 

strain, especially with imperfect amplitude of convergence. The 
small body is red, elevated, and angry-looking, and injected 
vessels run from it towards the cornea in the inter-palpebral 
space. This condition might be designated symptomatic, or func- 
tional encanthis. 

In like manner, temporary irritation of the structure is caused 
by the lodgment upon it of a foreign body, or by the presence of 
misplaced cilia which rub against it. This caruncle should be 
carefully examined when patients complain of irritation, lachry- 
mation, and inability to use their eyes with comfort. 

The excessive development of the hairs normally placed upon 
the caruncle, is called trichosis caruneuke. 

A few examples of tumors situated upon and growing from the 
caruncle have been recorded ; in two instances, the growth proved 
to be an adenoma (Prudden and Schirmer). 

Treatment. — Local irritations of this body may be relieved 
by the direct application of a mild astringent like alum, or soothed 
by touching it with tincture of opium. Foreign bodies, stiff hairs, 
and misplaced cilia must be extracted. A tumor is to be removed 
by the ordinary method of excision. 

Argyria Conjunctivae (Argyrosis). — Long-continued appli- 
cation of solutions of nitrate of silver to the conjunctiva may 
be followed by a brownish discoloration of this membrane. For 
this reason it is inadvisable to allow patients to use at home even 
a weak collyrium of this drug. Argyrosis is irremediable. 



DISEASES OF THE CORNEA. 259 



CHAPTER VII. 

DISEASES OF THE CORNEA. 

Under the general term keratitis are included the divers forms 
of inflammatory affections of the cornea, to which, according to 

the type, certain well-marked stages belong : cellular infiltration 
in the layers of the cornea going on either to absorption, or to 
the formation of pus; loss of the substance of the cornea lying 
over the infiltrated area, and the development of an ulcer ; loss 
of the transparency of the superficial corneal layers over an in- 
filtrated area, which has been converted into pus and created an 
abscess, with the final destruction of these layers by future de- 
velopment of the abscess ; the appearance of vessels in the cor- 
nea ; and the process of repair after loss of substance, or the 
period of cicatrization. 

Certain associated and subjective symptoms may be present in 
all forms of corneal inflammation. Among the former the mosl 
notable are the congestion of the vessels of the circum-corneal 
area; the possible involvement of the iris and ciliary body in the 
severe types of the affection, with the added signs of iritis ; and 
the development of pus in the anterior chamber. The subjective 
symptoms include diminution of vision, pain, photophobia, ex- 
cessive Iachrymation, and blepharospasm. 

Although it is customary to divide the many types of corneal 
inflammation into suitable groups, it is by no means possible to 
refer the disease in each instance to one or other of these divisions. 

Phlyctenular Keratitis or Kerato-Conjunctivitis. — This 
disease is characterized by the formation of single or mutiple 
vesicles or pustules on some portion of the cornea, and is accom- 
panied by dread of light and by blepharospasm. 

CAUSES. — The disease is quite cou-tautly seen in strumous 
subjects, rarely before the first year of life, most frequently in 
children before the age of puberty, and less commonly in adults. 



260 DISEASES OF THE EYE. 

The ordinary symptoms of struma may be present — enlarged 
lymphatic glands, prominent and swollen lips, and diseases of the 
joints and bones. 

This form of keratitis is in close connection with obstructive 
and inflammatory diseases of the nasal passages, and an irritating 
rhinitis is a constantly associated disorder, which, in turn, deter- 
mines an eczema about the nares. The affection often follows in 
the wake of measles or other acute exanthemata, and is distinctly 
under the influence of climate, being aggravated in warm and 
moist weather. 

Micro-organisms, which resemble the coccus flavus desidens, 
have been described with phlyctenular keratitis. 

In the belief of some authors, astigmatism bears a relation to 
its development. 

Symptoms. — The phlyctenules, which consist in the early 
stage of minute subepithelial collections of round cells, appear 
upon the cornea usually at or near the corneo-scleral junction. 
They vary in size from a poppy-seed to a millet-seed ; their tops, 
at first gray, speedily grow yellow, break down, and form super- 
ficial ulcers. They are accompanied by decided local congestion, 
increased lachrymation, and photophobia. 

The palpebral conjunctiva, always hypersemic, may remain 
translucent and bathed in tears, or the disorder is not infrequently 
accompanied by muco-purulent conjunctivitis. 

When the photophobia is seyere, the child buries its head 
deeply in the bedclothes ; the lids are spasmodically closed, 
rendering inspection of the eye difficult, at times well-nigh impos- 
sible. The dread of light and the blepharospasm are probably 
due to direct irritation of the corneal nerves, as Iwanoff found 
the cellular infiltration situated along the course of the neryes. 

The pustule, when it breaks down, forms the phlyctenular 
ulcer. 

This may remain at its original seat near the margin, or creep 
towards the centre of the cornea, followed by a bundle of thickly- 
crowded bloodvessels and form a special type of corneal inflam- 
mation known as fascicular keratitis. The bloodvessels, when 
the ulcer heals, disappear, but a stripe of opacity remains. 

Under the name marginal keratitis a variety of this disorder 



DISEASES OF THE CORNEA. 261 

exists, characterized by the development of numerous phlyctenules 
along the rim of the cornea, giving rise to a process which may 
cease here, or which by further invasion may produce vascular 
ulcers. 

More dangerous than any of the other varieties is the forma- 
tion of a single pustule, just at the corneal border, which speedily 
ulcerates and is surrounded by a yellow area of infiltration, with 
a strong tendency to perforate. 

If these inflammations recur constantly, the cornea becomes 
clouded, uneven from loss of epithelium, and covered by numerous 
superficial vessels, the whole forming the so-called phlyctenular 
pannus. 

Diagnosis. — This presents no difficulties, direct inspection 
rendering the nature of the disease evident. 

Prognosis. — The course varies greatly ; in mild cases healing 
takes place with only a slight loss of substance, and the resulting 
scar is scarcely discernible. 

Not so with the severe forms, in which there has been decided 
loss of substance, and a distinct scar-tissue remains, or in which 
deep ulceration with perforation occurs, or where constantly re- 
curring vascular ulceration leaves an uneven and roughened sur- 
face. In children of the strumous type, especially if their 
surroundings are unfavorable, phlyctenular keratitis is exceed- 
ingly intractable. 

Treatment. — In order to make a thorough application of the 
local remedies, the child's head should be taken between the 
surgeon's knees, and the lids separated, while the attendant holds 
the hands and body ; the cornea will usually roll out of sight, 
but gradually may be coaxed into view. Sometimes a lid-eleva- 
tor is useful, and a few whiffs of ether or of chloroform may be 
necessary. 

If much secretion is present, boric acid solution is to be em- 
ployed. Atropine drops should be instilled with sufficient fre- 
quency to maintain mydriasis. Cocaine, judiciously used, will 
allay the photophobia, but its continuous application when cor- 
neal ulcers exist is to be deprecated. Later, an ointment of the 
yellow oxide of mercury (gr. i-3j)> either with or without the ad- 
dition of atropine, may be employed, or calomel may be dusted 






262 DISEASES OF THE EYE. 

into the conjunctival sac, provided no form of iodine is being ex- 
hibited (see page 236). The eves should be protected with goggles, 
and the child encouraged not to bury its head in the bed-clothes. 

Douching the eyes with cold water will subdue the dread of 
light, and touching the ulcerated external commissure, which 
almost invariably exists in these cases, with a crystal of bluestone, 
as Roller has suggested, helps to relieve the blepharospasm. In 
severe cases the ulcerated fissure may be incised, or the lids may 
be forcibly separated. No doubt this acts by stretching or rup- 
turing a few fibres at the commissural angle, and relieves the 
spasm in the same manner as a similar manipulation is efficacious 
in fissure of the anus. 

The best possible hygienic surroundings must be obtained, with 
fresh air and wholesome food. Cod-liver oil, iron, quinine, often 
suitably given with pepsin, and arsenic, are the most acceptable 
internal remedies. 

The urine should be examined in all these cases ; and scrupulous 
attention to the condition of the alimentary canal is an important 
factor in the treatment. 

If rhinitis is present, a powder composed of equal parts of pul- 
verized camphor, boric acid, and subnitrate of bismuth is useful 
(Augagneur), especially if the parts are thoroughly cleansed with 
Dobell's solution before its insufflation into the nasal chambers ; 
or the affected mucous membrane may be painted with compound 
tincture of benzoin. In obstructive post-pharyngeal and nasal 
affections (hypertrophies, adenoid vegetations) the diseased areas 
must be treated on the principles of intra-nasal surgery. 

In stubborn forms of recurring vascular ulcer and deep ulcera- 
tion, especially in the fascicular type, the use of the actual cau- 
tery in the manner later described, is productive of excellent 
results. 

After healing, provided the condition of the cornea permits it, 
any refractive error should be corrected. There is reason to be- 
lieve that astigmatism may play some role in the production of 
keratitis in children ; hence its correction in patients constitu- 
tionally predisposed to this disease, even at a very early age, is 
a suitable prophylactic measure. 

In general terms phlyctenular inflammation of the cornea, 



DISEASES OF THE CORNEA. 263 

which has just beeD described, is a circumscribed, usually super- 
ficial keratitis, and is known under a variety of synonyms — 
lymphatic, scrofulous, vesicular, fascicular, and pustular — and 
when it appears in adults, assumes the form of a simple cor- 
neal infiltration. It furnishes the greatest number of ulcers of 
the cornea which are found in early life, and also a large group of 
those ulcers which are of primary origin, i. e. } where the disease 
starts in the cornea, the remainder of the group being caused by 
injury, abscess, depressed nutrition, etc. The entire series is in 
contrast to secondary ulcers, I. e., when the disease follows as the 
result of a severe inflammation of the conjunctiva, e. g., purulent, 
diphtheritic, or granular ophthalmia. 

The remaining inflammations of the cornea are divided by 
systematic writers into ulcerative and non-ulceraiive inflammations. 

Ulcers of the Cornea occur when the stao;e of infiltration has 
failed to terminate in absorption, and the overlying corneal 
layers have become disintegrated, with the formation of an open 
lesion. 

In addition to those which have been described with phlyc- 
tenular keratitis, corneal ulcers may be gathered into several 
groups : — 

1. Simple ulcer appears in the form of a small, superficial, gray 
lesion, associated with slight pericorneal vascularity, and results 
from the rupture of a phlyctenule ("pimple ulcer"), or from 
trauma. 

An ulcer, which from its situation is called small central ulcer, 
appears as a gray or gray- white opacity in the centre of the 
cornea, and is not accompanied with much vascularity or dread 
of light. The elevation is slightly cone-shaped until the whitish 
top breaks down into a shallow depression. 

Usually single, this form of ulcer may be multiple, and under 
any circumstances tends to recur. It is seen in young children 
who have been poorly nourished, and are of a strumous habit. 
While healing generally occurs with promptness, the tendency 
to recurrence leaves permanent opacity, which from its central 
situation, may seriously impair vision. If neglected, and in 
patients of poor nutrition, this ulcer occasionally forms an abscess 



264 DISEASES OF THE EYE. 

of the cornea, or changes it^ type and develops into the following 
variety : — 

2. Purulent or deep ulcer consists of an area of yellowish (puru- 
lent) infiltration, surrounded by a zone of hazy cornea, round or 
irregular in shape, centrally excavated, and with a tendency to 
travel inward toward perforation, but not to extend in a lateral 
direction. Like all severe types of corneal ulceration, it may 
be associated with inflammation of the iris and the formation oi 
pus in the anterior chamber ; if perforation takes place, an ad- 
herent scar or leucoma results. 

This ulcer is either primary from injury, and sometimes con- 
tains a foreign body as its nucleus, or it may be secondary to 
a violent grade of conjunctival inflammation. The subjective 
symptoms are pain, browache, congestion, and sometimes, though 
not necessarily, photophobia. 

3. Indolent ulcer (absorption ulcer) occurs under several forms : 
(a) Shallow central ulcer, with slightly turbid base, unattended 
with any considerable pain or photophobia, essentially chronic in 
its course, and healing finally with a faintly opaque remaining 
facet (facetted ulcer). 

(b) Excavated or gouged-out ulcer, often seen in children, most 
troublesome because it is so rebellious to treatment, has its seat 
near the corneal margin. It may be entirely overlooked on ac- 
count of the absence of congestion, and because in appearance, 
it is a small punched-out excavation with transparent bottom, 
and free from any opaque surrounding. The floor of the ulcer 
loses its translucency when healing is about to take place, and a 
few vessels of repair pass to its margin. 

(c) Reparative ulcers are seen when, as occasionally occurs, in 
the course of the healing of an ordinary corneal ulcer, this loses 
its turbidity and assumes a clear facet-like appearance. These 
are similar to the absorption ulcers which occur primarily, and 
which, unattended with injection and with local symptoms, may 
none the less extend inward and perforate the cornea. 

Indolent ulcers, in general terms depend upon some failure in 
the nutrition of the cornea, due to nervous disturbance. They 
are found in anaemic and scrofulous subjects, and are seen in 
cases of chronic trachoma. 



DISEASES OF THE CORNEA. 265 

4. Infecting or sloughing ulcer ( 'purulent keratitis). — I 'leers un- 
attended by vessels of repair, which spread widely from one border 
ami readily become complicated with hypopyon and iritis, and 
which are often the result of a trifling injury, usually affect 
elderly people and those whose nutrition is depressed. 

The most important type of these is the acute serpiginous or 
creeping ulcer of Saemisch. In the beginning a nearly central 
gray area forms, which ulcerates; its margins are sharp, and 
one, assuming the form of an elevated curve, is more decidedly 
opaque or yellow than the others, and is known as the arc of 
propagation. Immediately behind it, the ulcer with its gray floor 
seems deeper than the portion next to the corneal margin. 

The surrounding cornea is opaque, and the lesion spreads 
rapidly, at the same time growing deeper; iritis, irido-cyclitis, and 
hypopyon ensue, and perforation and extensive sloughing of the 
cornea are likely to occur. Usually the patient complains of 
severe brow pain, and the eye is intensely tender. Vision is 
reduced to mere light perception. In other cases, while the local 
lesion is severe, the subjective symptoms of inflammation are 
almost absent. 

Cause. — A sloughing ulcer of this character depends upon 
local infection, and most frequently results from an injury to the 
cornea from a chip of stone, a chestnut burr, beard of wheat or 
the like, which may cause an insignificant wound, but which, in an 
individual not disposed to kind healing, may terminate, through 
microbic infection (probably a special fungus), in this dangerous 
form of inflammation. This becomes more likely if the patient 
suffers at the time of the injury from catarrh of the lachrymal 
sac or from chronic conjunctivitis, the micro-organism being 
contained in the unhealthy secretion. The most marked types 
of this disease are seen in laborers in the harvest season. 

Hypopyon, to which reference has been made, may be seen 
with both small and large ulcers, and consists of a collection of 
pus in the anterior chamber, varying in extent from a mere line 
to a quantity which well-nigh fills the chamber. 

This appears as a yellow mass at the bottom of the anterior 
chamber, and is bounded above by horizontal margin. If the 
collection is fluid, its position will shift with movements of the 




266 DISEASES OF THE EYE. 

head ; if it is tenacious, no movement can be observed. The 

pus is caused by an aggregation of 

FlG - ?2, leucocytes, derived in part from the 

corneal disease, and in part from the 

iris, which is also inflamed. 1 

The combination of ulcer of the cor- 
nea and pus in the anterior chamber has 
received the name hypopyon-keratitis, 
which generally is limited to the type 

Hypopyon or a collection of , ., n . /» . . . ■, 

pus in the anterior chamber, described as infective or creeping ulcer. 

5. Abscess of the cornea consists of a 
purulent infiltration in the deeper layers of this membrane, over 
the centre of which, in the early stages, the epithelium is unbroken 
and prominent, but later, discolored and slightly sunken. 

The corneal zone immediately surrounding it is hazy. The 
margins of the collection are thicker and more prominent than 
its middle ; pus is seen in the anterior chamber ; the aqueous 
humor is turbid, and the iris inflamed. 

The subjective symptoms of severe corneal disease are com- 
monly present, but, as with sloughing ulcers, these indications 
may be absent. 

If the abscess is deep, the process may terminate without rup- 
ture of the upper layers and the formation of an open lesion, but 
generally it grows more yellow, notches laterally, bulges forward 
and finally bursts, leaving a more or less ragged ulcer covered 
with tenacious pus, and pursuing a course similar to or identical 
with that described under sloughing or infecting ulcer, of which, 
i ii< Iced, abscess is the first stage. It will hence be seen that ab- 
scess of the cornea, according to its stage, may belong to the 
non-ulcerative or ulcerative lesions of the cornea. 

Causes. — Abscess of the cornea results from an inoculation of 
the affected area with the pathogenic micro-organisms which are 
the cause of suppuration, these having gained entrance through 

1 Onyx, a term frequently applied to a supposed accumulation of pus 
between the layers of the cornea, and settling in its most dependent portion 
below an abscess, should not be retained, as it describes an appearance which 
is incorrectly interpreted (Berry). 



DISEASES OF THE CORNEA. 267 

an abrasion in the epithelial cells. As already stated, simple 
ulcers, through neglect, may form abscesses; and they follow 
slight traumata when the latter become infected, especially by 
unhealthy lachrymal secretion, and are seen in association with 
violent types of conjunctival inflammation. A certain num- 
ber of cases have been ascribed to cold; in still others no defi- 
nite cause can be ascertained. 

A variety of abscess of the cornea, non-inflammatory in char- 
acter, without any healing tendency, and with an entire absence 
of subjective symptoms, has been described as occurring in 
scrofulous children under eight years of age. The character 
of the disease and the constitution of its subjects have led some 
to consider it a form of tuberculosis of the cornea. 

Most violent forms of suppurative keratitis occur during the 
convalescent stages of smallpox, though pustules rarely form 
upon the cornea. Abscess of the cornea occasionally accompa- 
nies scarlet fever, measles, typhoid and typhus fever, and in 
these cases must be regarded as metastatic, the pathogenic ma- 
terial having been conveyed through the blood, and not as com- 
ing from without, as in the more usual examples. 

6. Ulcus rodens is the name applied by Mooren to a creeping 
ulcer which begins at the upper edge of the cornea as a super- 
ficial lesion, separated from the healthy portion by a gray, 
opaque rim, which is undermined. Although vessels may pass 
to it and cicatrization apparently begin, it relapses cpjickly 
and progresses forward, until the whole cornea has been trav- 
ersed and sight is destroyed. The cornea is not perforated in 
this disease, which is a rare form, attacking elderly and de- 
pressed subjects. 

7. Circular ulcer (marginal ring ulcer, annular ulcer) occurs in 
the form of a deep groove, at the corneal margin, unaccompanied 
by much infiltration, which gradually progresses until it may 
entirely girdle the cornea and cut it off from its nutrition. Pho- 
tophobia, injection, lachrvmation, and other irritative symptoms 
are not prominent, but perforation of the cornea and prolapse of 
the iris are common. The disease is seen in debilitated subjects. 

Another variety of ring ulcer is formed as the result of a mar- 
ginal phlyctenular keratitis (page 260), probably by the coa- 



268 DISEASES OF THE EYE. 

lescence of a number of small foci. Ring ulcers are also seen in 
catarrhal and purulent conjunctivitis, and in the latter condition 
may prove especially dangerous if they are hidden by the che- 
motic conjunctiva. 

8. Dendriform ulcers (keratitis dendritica ulcerans mycotiaa i 
fur row-he ratitis, keratite ulcereuse en sillons etoiles) are a form 
of keratitis probably dependent upon a special micro-organism, 
and appear in branch-like ramifications, having a superficial situ- 
ation, with slight, knob-like swellings at the end of the branches. 
The inflammation manifests itself in two forms. 

In one, from the beginning, the symptoms include photopho- 
bia, lachrymation, strong bulbar injection, swelling of the upper 
lids, and absence of the epithelium over the furrow-formed rami- 
fications — an implantation of the process in the deeper corneal 
layers. 

In the other, the disease assumes a subacute or torpid charac- 
ter, with practical absence of severe irritative symptoms and loss 
of the covering epithelium — a limitation of the lesion to the 
superficial layer. In the first form the opacity is confined to 
the axis of the furrows ; in the second, to the border. After 
healing, the scars have the same general configuration which was 
present during the stage of ulceration. The disease is rare and 
occurs in both sexes. 

The cause, further than its probable mycotic nature, is un- 
known. Fuchs thinks some cases may arise from febrile herpes 
of the cornea (page 281), by the increase and coalescence of the 
small blebs. Malaria originates a keratitis in which the lesion 
consists of a peculiar, narrow, serpiginous, superficial ulcer, with 
lateral offshoots, like the skeleton of veins in a lanceolate leaf, 
usually accompanied with photophobia and lachrymation, and 
sometimes ushered in with severe supra-orbital neuralgia (Kipp). 1 

1 It will be observed that several varieties of corneal ulcers have one symp- 
tom in common, that of creeping across the corneal surface from their points 
of origin, viz., fascicular keratitis ("snail-track ulcer"), Saemiseh's ulcer, 
rodent ulcer, and dendriform ulcers, and for this reason they may all be 
grouped under the general term, serpiginous ulcers, as suggested by Fuchs. 
Ring ulcers possess somewhat the same peculiarity exercised in a circular 
manner. 



DISEASES OF THE CORNEA. 269 

9. Exhaustion-idaer (kera&o-rmkwia) may appear as an exten- 
sive ulceration in the centre of the cornea, or as a ring-abscess 
at its circumference. The tissue speedily is converted into a 
slough, which drops out, and an extensive perforation results. 

In other instanees the sequel is described as a species of atrophy 
of tJtc coined, which is converted into a whitish, flattened plate 
(Schmidt-Rimpler). 

One or both corner may be affected, and the usual cause is 
exhaustion after acute illness, or after prolonged diarrhoea or 
dysentery. A similar softening and sloughing of the cornea may 
be the result of ophthalmia neonatorum (page 223), or cataract 
operations which have become septic, and they are seen in a per- 
fect type in xerotic keratitis (page 279). 

Treatment of Ulcers of the Cornea. — It is not pos- 
sible to lay down definite rules for the treatment of all forms 
of corneal ulceration — this must be governed by the exigencies 
of each case ; but certain principles are common to the various 
types. 

Acute stage : Pain and photophobia. — These should be relieved 
by the plans already suggested in treating phlyctenular keratitis. 
In mild cases, atropine, a lotion of boric acid, and dark glasses 
will usually suffice. The use of blisters and setons, recom- 
mended in chronic cases, is seldom required, but a leech to the 
temple in sthenic types may be needed. 

Cocaine will relieve photophobia temporarily, but its con- 
tinuous use in corneal ulceration is positively harmful. If a cor- 
neal ulcer is accompanied by much dread of light, the methods 
described under phlyctenular keratitis may be employed. 

Whenever corneal ulceration is accompanied by conjunctivitis 
and discharge, the inner surfaces of the lids should be brushed 
over with a weak solution of nitrate of silver (2-5 grains to the 
ounce), and the cul-de-sac carefully cleansed with a boric acid 
solution, or the collyrium of bichloride of mercury, as often as 
accessary to free the eye from accumulated secretion. 

SvbaGUite a ad Torpid Stage. — After the subsidence of the acute 
symptoms, or when the ulcer from the beginning is unaccom- 
panied by these, local stimulation should be practised. This is 



270 DISEASES OF THE EYE. 

best clone with an ointment of the yellow oxide of mercury pre- 
pared by the following formula : — 

Yellow oxide of mercury ...... 1 grain 

Sulphate of atropine ....... \ grain 

Vaseline ......... 1 drachm 

A small portion to be introduced between the lids night and morning. 

The atropine maintains the mydriasis and at the same time 
is sedative. When these actions are no longer needed, the atro- 
pine may be omitted from the salve, and the mercurial compound 
alone employed. Finely powdered calomel dusted into the eye 
is also of excellent repute. In like manner iodoform or aristol, 
in salve or powder, may be tried. Direct stimulation with a 
probe dipped in laudanum, or a weak solution of nitrate of silver 
(five grains to the ounce), is a useful procedure, either to encourage 
the healing of an ulcer which has passed into the subacute stage, 
or to excite curative reaction in one that has been torpid from its 
origin. Eserine is indicated, instead of atropine, in small slug- 
gish ulcers, unattended by active symptoms. 

Deep and Sloughing Ulcers. — It was a universal, and is still a 
common practice to instil atropine drops, because of their anodyne 
effect and because they lessen the liability to iritis, although 
mechanical and antiseptic measures, as now employed, have ren- 
dered the need of mydriasis less urgent than in former times. The 
alkaloidal solutions should be sterile, as a simple ulcer may be 
infected with impure drops and pass into a sloughing condition. 

In some cases eserine is the better drug, either because it stops 
the migration of white blood-corpuscles, or promotes absorption 
through dilatation of the ciliary vessels, or limits the sloughing 
process. Furthermore, abnormal intraocular tension is lowered 
by the action of the drug. The strength of the solution may be 
from one-quarter to one grain to the ounce, the latter being 
unnecessarily active in most cases. Deep ulcers near the mar- 
gin are those most suited for its application. One or two 
drops of the eserine solution should be instilled from three to 
six times daily; and as, under its influence, congestion of the 
ciliary body and iris may ensue, as well as brow-pain, these 
should be counteracted by using a few drops of the atropine lotion 
at night. The combination of the drugs thus employed in cases 



DISEASES OF THE CORNEA. -71 

where do iritic complications are present is productive of the 
most happy results. 

Pain is relieved and the process of repair encouraged by the 
frequent application of hot compresses (see page 225). Hot water 

(150° F.) dropped directly upon the ulcer is recommended by 
Lippincott. The cul-de-sac and lachrymal passages must be 
irrigated frequently with antiseptic collyria — a saturated solution 
of boric acid, bichloride of mercury (1-10,000), or aqua chlorini. 

(a) Impending Perforation. — When perforation of the cornea 
is liable to occur by extension of the ulcer, a dry antiseptic com- 
pressing bandage should be applied, removed when the necessary 
local applications are made, and again reapplied. Long-continued 
use of the bandage may be followed by eczema of the lids. This 
should be treated by dusting the parts with calomel. Catarrh of 
the conjunctiva and dacryo-cystitis contraindicate the use of the 
bandage unless the danger of perforation is imminent. 

If bulging forward of the floor of the ulcer indicates that per- 
foration is imminent, the intraocular tension should be lessened 
by paracentesis of the cornea. This operation is described on 
page 599. After its performance, eserine is instilled, if the ulcer 
has a peripheral situation, atropine, if it is central ; the bandage 
is reapplied and the patient placed at rest. It may be necessary 
to repeat the operation on several days. Intense pain will often 
be thus speedily relieved and healing rapidly result. 

(b) The Spread of Local Infection. — If in spite of such treat- 
ment the corneal ulcer continues to spread, either in the form of 
a lesion creeping across the face of the cornea, or by passing 
inward through its layers, the process must be stopped by one 
of several means: (1) Scraping with a curette; (2) the direct 
application of a suitable chemical which combines the properties 
of a germicide and a caustic ; and (3) the actual cautery. 

(1) The ulcer may be curetted with a sharp spoon (under a 
boric-acid spray — De Wecker), all the sloughed material removed, 
the edges pencilled with a sublimate solution (1-2000), iodoform 
dusted upon its surface, and a dry sterile bandage applied. 
Mules advises softened iodoform w 7 afei*s. 

(2) The chemical substances commonly employed are nitrate 
of silver and carbolic acid. The former, in the strength often to 



272 DISEASES OF THE EYE. 

twenty grains to the ounce, is applied directly to the seat of 
ulceration (care being taken to avoid the surrounding cornea), by 
means of a probe ou which has been twisted a thin band of 
absorbing cotton, or the point of a pencil of lunar caustic may 
be gently pressed against the sloughing tissue. Carbolic acid 
(liquid) may be employed in the same manner as the silver 
solution ; or tincture of iodine. 

(3) The actual cautery may be either a small Paquelin or 
galvano-cautery ; when neither of these is at baud, a knitting 
needle or platinum probe, heated red hot in the flame of a 
Bunsen burner, will suffice. The edge and floor of the ulcer 
should be gently but thoroughly burned. Usually one cauteri- 
zation is sufficient, but in the event of failure to destroy all the 
sloughing material, the operation should be repeated on the fol- 
lowing day. (See also page 600.) Cocaine renders the opera- 
tion painless, but there is no objection to general anaesthesia in 
nervous patients. 

If the surgeon is careful to touch only those portions involved 
in the ulcerated process, the resulting scar will not be greater 
than would have been the case had the ulcer secured cicatrization 
without such treatment. Fluorescin will show the extent of the 
ulcer, and mark out the area to be cauterized. 

The actual cautery is indicated in all sloughing ulcers which 
fail to show improvement after milder measures have been tried, 
and in torpid or relapsing ulcers, without much reaction, where 
a decided stimulant is needed. In certain types of infecting 
ulcers, of serpiginous character, typified by Saemisch's ulcer, 
and also in annular ulcer and the furrow-keratitis, where the 
apparent local infection is less marked, the actual cautery is 
the most potent agent to arrest the process. In rodent ulcer it 
is one of the few means that are at all efficacious. Roller ad- 
vises iodine. 

Abscess cud Hypopyon. — The pus should be evacuated. If 
the abscess is unbroken, its anterior wall may be incised with a 
delicate knife, and the subsequent treatment conducted on the 
principles laid down for sloughing ulcers. If the abscess haa 
burst, and is complicated with hypopyon, the latter may be en- 
couraged to absorption by paracentesis of the cornea in its lower 



DISEASES OF THE CORNEA. 273 

portion, or by the more formal procedure of Saeraisch, in which 
a section is made directly through the diseased area (page 600). 

The use of the actual cautery and the antiseptic treatment of 
ulcers have to a great degree replaced the operation of Saemisch, 
and in many instances absorption of the products of a hypopyon- 
keratitis will follow the non-operative treatment already described. 

Perforation. — If perforation occurs, the vigorous use of atro- 
pine or eserine, according as the lesion has a central or peripheral 
situation, aided by gentle efforts at reposition with a probe, a com- 
pressing bandage, and rest in the recumbent posture are the first 
measures. 

In the event of failure, or in any event, if the prolapse is a 
large one, the iris should be drawn forward through the aperture 
and excised close to the cornea, provided not more than two or 
three days have elapsed since the accident. After excision, the 
aperture may be covered with a conjunctival flap taken from the 
bulbar conjunctiva, twice as large as the original opening, into 
which it is gently inserted with a probe. A firm compressing 
bandage, not to be disturbed for three days, is then applied. 
This method is said by the author, Gamo Pinto, to secure a flat 
cicatrix, often without any attachment of the iris, although an- 
terior synechia usually results even from the smallest perforation. 
If the prolapse has been large, a more or less complete staphyloma 
will follow in spite of vigorous bandaging and the use of eserine 
or atropine. 

RtsumA of the Local Measures. — The most useful antiseptics 
during corneal ulceration are boric acid (gr. xv-3j), bichloride of 
mercury (1-8000 or 1-10,000), and iodoform in salve or powder. 
For the latter drug may be substituted iodol and aristol, which, 
however, do not seem to surpass it in beneficial results. Chlorine 
water, in half strength, is much employed by some surgeons. 

Of the local measures to stimulate healing in sluggish ulcers, 
or to hasten the process of repair, laudanum directly applied or 
in the form of a collyrium, and yellow oxide of mercury in salve 
(Pagenstecher's salve), are most commonly employed. The latter 
remedy may be replaced by an ointment of iodideof potassium, iodol, 
aristol, or iodoform. Europhen (in salve or powder) and dermatol 
is 



274 DISEASES OF THE EYE. 

have not acted favorably, according to the author's experience, in 
any stage of corneal ulceration. 

The aniline dyes, in the form of blue and yellow pyoktanin, 
are useless and sometimes harmful. Subconjunctival injections 
of corrosive sublimate have been recommended bv Darier in 
sloughing ulcers; the author's results have not been satisfactory. 

The indications for a mydriatic or a myotic have been given. 
If for any reason (idiosyncrasy) atropine is not tolerated, mydri- 
asis may be maintained with hyoscyamine or daturine ; and if 
eserine creates irritation, pilocarpine in double the strength may 
be tried. It is important to remember that cocaine has no place 
in the treatment of corneal ulcers, save only as a temporary 
remedy, for example, to produce anaesthesia preparatory to ope- 
ration, or to remove a foreign body. Its continued use will in- 
crease the ulceration. 

Of the methods described to check infecting ulcers, curetting, 
iodoform and the bandage, and touching with nitrate of silver 
or iodine are the most generally applicable, unless the conditions 
are present which are believed to demand the actual cautery. 

Associated Conditions. — The treatment of conjunctivitis com- 
plicating ulcer of the cornea in no wise differs from that 
suited to ordinary cases. An ulcer should always be carefully 
examined for the presence of a foreign body, which may be 
covered by a small slough, while misplaced cilia are fruitful 
sources of corneal irritation and may hinder the prompt healing 
of ulcers. They should be removed with epilating forceps, or 
destroyed by galvano-puncture. 

The lachrymal passages should be explored, and if strictured, 
rendered patent, while irrigation of the lachrymal canal with a 
four per cent, solution of boric acid, or 1-8000 solution of bichlo- 
ride of mercury, is of material aid in the treatment of infecting 
ulcers, because this passage is commonly the seat of unheal! hy 
secretion. At the same fime the naso-pharynx needs exploration 
and treatment of diseased conditions. 

The teeth should always be examined, and if faulty, the case 
turned over to a competent dentist. The frequent relation of 
carious teeth to corneal ulceration is well established, and the 
irritation of a new dentition in young children has been found 



DISEASES OF THE CORNEA. 275 

to be the cause of abscess or ulcer of the cornea. In brief, the 
entire cephalic mucous membrane (Harrison Allen) should be 
explored, because, in one or other of its component parts, it may 
be the seat of disease, which, even if it is not the cause of the 
co-existing corneal ulceration, is none the less responsible for 
retardation in the healing process. 

( institutional Treatment. — Hygiene, diet, and judicious internal 
medication are of paramount importance. The patient should 
not be secluded in a dark room, but, with eyes properly protected 
with ffoo-oles, go out into the fresh air every dav. The diet 
must be nutritious and easily digested ; tea, coffee, candies, and 
pastries are to be forbidden. 

If struma is present, cod-liver oil, lacto-phosphate of lime, 
and iodide of iron or syrup of hydriodic acid are indicated ; 
anaemia is best treated with the tincture of the chloride of iron 
or with the carbonate of iron ; any suspicion of malaria requires 
the use of quinine and arsenic. The syphilitic taint, which may 
be present without being the direct cause of the ulcer, indicates 
the iodides, and mercury, especially in the form of the bichloride. 
As gout has been shown to be the cause of some corneal ulcers, 
this, as well as the rheumatic dyscrasia, must be searched for, 
not alone as an active manifestation, but also as a hereditary 
disease, and suitable remedies exhibited : citrate of lithium, 
mineral waters, iodides, colchicum, salicylic acid, salol, etc. 

A very strict inquiry into the condition of the alimentary 
canal should never be forgotten, as this may not be in a condi- 
tion properly to receive the tonics which are indicated. In 
children, calomel is a useful laxative ; in older patients, the 
salines and saline waters are often necessary. 

The urine should be carefully examined for albumin and 
sugar, and for the products which indicate imperfect assimilation. 

A very important element in the successful management of 
cases of sloughing ulcers, especially in subjects of depressed 
nutrition, is the maintenance of proper circulation. This is 
best secured by the exhibition of brandy or whiskey in milk, 
and of strychnine or digitalis as a vaso-motor or cardiac tonic. 
Severe pain may be alleviated by opium or morphine in suitable 



276 



DISEASES OF THE EYE. 



cases ; the drug also has a favorable influence upon the ulcer- 
ation. 

Results of Corneal Ulceration. — Opacities more or less 
permanent follow all ulcerations of the cornea. If the opacity is 
slight, it is spoken of as a nebula or macula; if dense, as a 
leucoma. 

It is evident that upon the position of the opacity in the cornea 
depends its influence upon vision. The more central it is, or 
rather the more directly it encroaches upon the pupillary region, 
the greater will be the disturbance of direct vision. Inequalities 
in the curvature of the cornea distort the retinal images, and are 
fruitful sources of irregular astigmatism. 

When perforation has followed ulceration and the iris has 
remained entangled in the aperture, the attachment is called an 
(interior synechia; the corneal scar to which the iris is fastened, 
receives the name adherent leucoma. An eye thus afflicted may 
become quiet and retain, either with or without operative in- 
terference, useful vision; but may also be a continual source of 
annoyance, subject to recurring attacks of inflammation, and 
may originate sympathetic irritation in the fellow eye. 



Fig. 93. 



Fig. 94. 





Complete staphyloma of the 
cornea. 



Section of an eyeball with complete 
staphyloma of the cornea. 



The distension of a cicatrix, to whose inner surface the iris is 
attached, constitutes a corneal staphyloma, which is called total, 
when the entire cornea is involved, partial, when only a portion 



DISKASKS OF THE CORNEA. 



277 



is included, and racemose, when perforations have occurred at 
various points. 

The mechanism of the development of staphyloma is briefly 
as follows: A perforation takes place, and the iris falls forward 
and attaches itself to the opening, or protrudes through it, becom- 
ing- fixed there by the lymph thrown out in the proeess of repair. 
The scar tissue which remains fails to withstand the intra-ocular 
tension, and that portion of the cornea is pushed forward beyond 
its normal limits, forming a pouch-like deformity. (Fig. 95.) 

Fig. 95. 




Partial staphyloma of cornea, showing: the attachment of the iris to its inner 
surface (Meyer). 

The protrusion may flatten down, and under the influence of fresh 
inflammation bulge forward again, or may extend between the 
palpebral fissures and prevent the lids from closing (consult 
Fig. 93). Staphylomata, the result of ulceration, are more or 
less opaque, because they represent the scar tissue which has 
formed after the rupture of the membrane. Corneal staphy- 
lomata, which are not opaque and have not formed under the 
influence of an inflammation, also occur, and will presently be 
described. 

If after inflammation of the cornea, with loss of its superficial 
layers, the intraocular pressure bulges forward the remaining 
lamina into an opaque elevation, the condition is called kereeta- 
sia. This differs from an ordinary partial staphyloma because 
there has been no perforation, and the iris tissue is not involved 
in the process. 

If all the layers of the cornea down to the posterior elastic 
lamina are destroyed, and this protrudes through the opening in 
a small, translucent hernia-like pouch, surrounded by a rim of 
opaque cornea, it is known as a kemtoeele. 



278 DISEASES OF THE EYE. 

An orifice remaining after a wound, or more commonly because 
of the failure of an ulcer to heal, is designated fistula of the 
cornea. It may last for a long period and stubbornly resist 
efforts at cure. It has beeu recommended to touch the mouth 
of the fistula with a point of lunar caustic, and even to pare the 
edges and introduce a corneal suture. 

Treatment of the Results of Corneal Ulceration. — 
Satisfactory results follow massage of the cornea. The massage 
movements should be made in a circular and radial manner, over 
the cornea, through the closed lids, after the introduction of a 
small piece of the yellow-oxide-of-mereury salve, into the con- 
junctival cul-de-sac. Some irritation accompanies the method, but 
may be allayed by the occasional use of a collyrium of boric acid 
and cocaine. 

Recently Alleman has revived the use of galvanism for 
the removal of corneal scars. A suitably prepared electrode is 
connected with a battery, the cathode being applied directly to 
the anesthetized surface of the cornea, and the anode to the soft 
tissues of the cheek. Usually a current of from one to one and 
one-fourth milliamperes gives the best results. The seance 
lasts at the beginning for one minute at a time, and is gradually 
increased to three and four minutes. Great care should be taken 
not to produce too much reaction. The author reports very 
favorable results. 

Dense leucomas cannot be influenced by the practice of massage. 
A sufficient number of cases treated by galvanism have not been 
reported to determine its value. Vision may be improved by 
an iridectomy for new pupil, and the appearance of the eye, by 
tattooing the cornea with India ink. In recent times attempts 
have been made at transplantation of rabbit's cornea for the 
relief of dense central opacities, but, although Von Hippel has 
reported some instances in which he was encouraged, the method 
does not seem likely to meet with sufficient success to warrant 
its adoption. 

The treatment of staphyloma in the first place is preventive, and 
those measures already described in connection with impending 
perforation of the cornea, and perforation after its establishment, 



DISEASES OF THE CORNEA. 279 

are indicated, namely, a compressing bandage and the use of 
eserine or, under some circumstances, atropine. If in spite of this 
the bulging continues, paracentesis of the anterior chamber, or an 
iridectomy opposite the clearest part of the cornea, may be per- 
formed. If the disease has been so extensive that a complete 
and unsightly staphyloma lias formed, which is the seat of pain 
and a source of danger to the fellow eye, excision of the globe is 
indicated, or one of the various substitutes for the operation of 
enucleation. 

Xerotic Keratitis (Kerato-malacia, Necrosis Corneoe, Infantile 
Ulceration of the Cornea, with Xerosis of the Conjunctiva.) — This 
disease is characterized by a dryness of the conjunctiva and a 
destructive ulceration of the cornea, and usually appears in 
infants during the first year of life. 

CAUSE. — Formerly the disease was believed to be dependent 
upon encephalitis, a theory no longer tenable. It occurs only 
in anaemic, badly nourished individuals. It has been seen ac- 
companying meningitis, measles, and variola, and among children 
with diarrhoea, and those who are inmates of homes whose sur- 
roundings are bad. Bacilli have been found, but the special 
microbe, if it exists, has not been isolated. The disease is not a 
common one. A somewhat similar condition has been described 
in the eyes of negro children in the South (Kollock). 

Symptoms. — In the beginning there are conjunctival conges- 
tion and laohrymation, but the peculiarity of the disorder is the 
development of the appearances described under epithelial xerosis 
(page 250), in connection with the corneal lesions A gray haze, 
rapidly turning into ulceration, appears in the cornea, followed 
by inflammation of the iris, and the formation of hypopyon. 
Perforation of the cornea, and destruction of the eyeball, may 
result. Both eyes as a rule are affected, one earlier than the 
other. 

The prognosis is very unfavorable ; the patients usually die of 
the wasting disease which has occasioned the trouble, or of an 
intercurrent pneumonia. In one case streptococci were found in 
the local lesions, and foci of these micrococci scattered throughout 
the body. 



280 DISEASES OF THE EYE. 

Treatment. — This resolves itself, besides the ordinary treat- 
ment of severe corneal ulceration, into the administration of the 
internal remedies which are indicated by the general state of the 
patient. 

Neuroparalytic Keratitis is the name a] (plied to an ulcerative 
inflammation of the cornea, which arises when this structure be- 
comes anaesthetic, because it is severed from the influence of the 
trigeminus. 

Cause. — The corneal lesion has been ascribed to a trophic 
change; to the lessened power of resistance which the cornea in 
its insensitive condition presents to external injuries; to tin- 
irritation of the fifth nerve by the lesion; to micro-organisms; 
and to increased evaporation from the surface of the cornea. 

Disease of the Gasserian ganglion, or its removal for trifacial 
neuralgia, disease of the nuclei of the fifth pair, periostitis of the 
orbit, syphilitic deposits, and fracture of the skull, may cut off the 
trigeminal influence and cause the affection. A combination of the 
trophic and traumatic theory best explains the disorder ; foreign 
substances remain undetected upon the insensitive cornea, whoa 
resisting power is weakened through loss of trophic influence. 

Symptoms. — The keratitis begins in the true corneal tissue, 
and rapidly spreads forward until the central necrosis or slough 
separates, and perforation of the cornea with prolapse of the iris 
occurs. The anterior chamber may contain pus, or pus mixed 
with blood. Beyond and around the central abscess, the corneal 
tissue is comparatively clear, but in the periphery there are 
secondary foci of infiltration, closely connected with inflamma- 
tion of the neighboring conjunctiva. The surface of the cornea 
and conjunctiva is ausesthetic. The intraocular tension is dimi- 
nished. There may be considerable pain and irritation, or these 
symptoms may be absent. 

The prognosis is extremely unfavorable, and in spite of treat- 
ment destructive inflammation commonly results. 

Treatment. — The affected eye should be excluded from the 
influence of external irritants, either by a carefully applied anti- 
septic bandage, a Buller's shield, or by stitching together the lids. 
Experimental evidence indicates the propriety of preventing evap- 
oration by keeping the eye in a moist atmosphere. 



DISEASES OF THE CORNEA. 281 

Herpes Corneae. 1 — The corneal lesions associated with herpes 
zoster ophthalmicus have been described on page 192. The pre- 
sent disease consists of a vesicular eruption upon the cornea, 
which breaks down and forms an ulcer, characterized by a denu- 
dation of epithelium not unlike that produced by injury. 

Causes. — Homer has described herpes of the cornea with 
whooping-cough, intermittent and typhoid fever, and in general 
terms, with those affections in which herpes of the lips and nose 
are found. It is seen in acute and subacute disease of the pos- 
terior nares and pharynx, and also in affections of the respiratory 
apparatus generally (pneumonia — bronchitis). 

Symptoms. — The disease begins with a series of transparent 
vesicles upon the cornea, which have been compared to a string 
of small beads. The vesicles are placed in a circle, or run in a 
diagonal line across the cornea. They speedily rupture and 
have an open patch, deprived of epithelium, which is anaesthetic 
and has irregularly serrated margins, upon which the remains of 
vesicles may be seen. 

The progress of repair is slow, and is often interrupted by 
the reappearance of fresh vesicles. The disease may be com- 
plicated with pus in the anterior chamber and iritis. Pain in 
the eye and brow, photophobia, lachrymation, and a gritty sensa- 
tion are the subjective symptoms. 

Treatment. — This consists in relieving the general condition ; 
usually quinine in full doses is indicated. Locally, in the stage 
of irritation, atropine with cautious use of cocaine, warm com- 
presses and dark glasses are needed. Calomel dusted into the 
eye is recommended. After the formation of the ulcer the 
treatment is conducted on general principles. Eserine now may 
be substituted with advantage, if there is no iritis, and in stub- 
born cases a light application of the actual cautery is useful. 

Keratitis Bullosa in many instances is a symptom and not a 
separate disease, inasmuch as it consists of the formation of one 
or more small blebs of short duration (K. Vesiculosa), or of 
larger blebs of more enduring existence (K. Bullosa), upon the 

1 This term, as Homer observes, is often incorrectly used as synonymous 
■witli phlyctenular keratitis. 



282 DISEASES OF THE EYE. 

cornea of an eye, the subject of iridocyclitis, interstitial keratitis, 
or glaucoma. 

The cause of this affection, which formerly was attributed to a 
mechanical effect due to increased intraocular tension, is not entirely 
clear, but probably depends, according to Fuchs, upon an abnor- 
mality of the lymph circulation, in which a stasis takes place 
resulting in oedema of the cornea and a blister-like elevation of 
the corneal layers and the epithelium. Sometimes moderately 
large vesicles form upon a cornea otherwise normal, and in one 
reported case malaria was believed to be the chief factor in their 
causation. 

The symptoms, in addition to the formation of the blebs, are 
burning pain, photophobia, injection of the bulbar conjunctiva, 
and rupture of the vesicles, leaving an abrasion which may go on 
to ulceration. There is a strong tendency to recurrence, and with 
each new formation of vesicles the violent inflammatory symptoms 
are repeated. 

The treatment consists in puncture of the blebs, and suitable 
local measures, according to the causative disease. In bad cast - 
iridectomy and even enucleation may be needed. The recurrent 
character and the remissions which have been described have 
suggested the use of antiperiodic doses of quinine ; and these have 
been given with good results. 1 

The second group of corneal inflammations is the non-uleera- 
tive, and includes a variety of affections usually unattended by 
the development of ulcers, but among which some are described 
that occasionally present the lesions seen with ulcers in the course 
of their development. Abscess of the cornea, if it remains with 
unbroken boundaries, is a suppurative but non-ulcerative affec- 
tion and naturally belongs in this group. As in many instances 
its walls break down and an open ulcer results, it has been 
described with the ulcerated forms of corneal disease. 

1 Herpes of the cornea, the corneal complications of herpes zoster ophthal- 
micus (page 192) and the two varieties of the keratitis just described have 
been gathered by Fuchs under the general caption of keratitis with vesicle 
formation, to which category he adds that type of corneal disease known as 
relapsing erosion of the cornea. 



DISEASES OF THE CORNEA. 283 

Vascular Keratitis is a superficial vascularity and opacity of 
the cornea, and is seen in pannus caused by granular lids (page 
243) and in phlyctenular pannus, the result of many relapses of 
phlyctenular keratitis (page 261). 

Another form of vascular keratitis is characterized by the 
formation of two opposite vascular areas at the upper and lower 
margins of the cornea, which approach each other until the vascu- 
larization is complete. The disease is met with in young adults 
and in unhealthy, scrofulous and underfed children. The second 
eye usually is attacked, and, as has been pointed out by Carter, 
the character of the disorder indicates a perverted action of the 
nerves which govern the areas affected, and places it in analogy 
with herpes. 

Symptoms. — These begin insidiously with slight intolerance 
of light, preceding the appearance at the upper margin of the 
cornea of a crescent of closely arranged bloodvessels, which, as 
they advance, push before them a border of corneal opacity. 
Simultaneously the same appearances become manifest at the 
lower margin. Clearing begins at the borders, and the whitish 
opacity which remains leaves the centre last of all. In the early 
Btages the disease may be mistaken for conjunctivitis. All cases 
must be regarded with anxiety, and some do not clear up entirely. 
(Compare page 285.) 

Treatment. — Local irritants are contraindicated. Atropine, 
cocaine, and warm fomentations in the early stages, and later 
a salve of the yellow oxide of mercury, or calomel, are useful. 
The best internal treatment is a prolonged course of iron and 
bichloride of mercury. Iridectomy for new pupil may be neces- 
sary, and the convex side of the vascular crescent may be touched 
with the galvano-cautery. 

Interstitial Keratitis (Syphilitic, Inherited, Specific, Parenchy- 
matous, Strumous, and Diffuse Interstitial Keratitis). — This is a 
diffuse keratitis in which a chronic inflammation of the whole thick- 
ness of the cornea takes place, until, usually without ulceration, 
but always with superficial or deep vascularization, the cornea 
passes into a condition of universal thick haziness. 

CAUSES. — The majority of cases of interstitial keratitis are 
due to inherited syphilis ; in rare instances it is caused by 



284 DISEASES OF THE EYE. 

acquired syphilis. In spite, however, of the not infrequent occur- 
rence of this affection, the exact cause of its development is not 
always of ready demonstration. Evidence of inherited syphilis 
is present in between sixty and seventy per cent, of the cases, 
and it is probable that this percentage would rise higher, if the 
separation of typical cases was made from such as are only similar 
in appearance to the true disease. 

In addition to the influence of hereditary syphilis this disease 
has been attributed to rachitis, scrofula, malaria, rheumatism, and 
depressed nutrition. It is occasionally seen in animals. 

It is most frequently seen between the ages of five and fifteen, 
occasionally as early as three years, but rarely after thirty. A 
few cases are on record as late as the sixtieth year of life. Sonic 
statistics show that interstitial keratitis is more frequent in females 
than in males. The average age for males to be attacked is about 
seventeen, while women are affected a year and a half earlier, 
because a large number of cases occur about the supervention of 
menstruation. The greater immunity of the male sex from this 
disease does not, however, appear in all cases, other statistics 
showing an equal susceptibility, and still others a greater liability 
on the part of males. 

Interstitial keratitis appears to have been aggravated by the 
development of menstruation, and also to have undergone im- 
provement by establishment of the menstrual molimen. It is 
probable that the affection occasionally arises in utero, and a con- 
genital form of interstitial keratitis, not differing in appearance 
from the ordinary or post-natal form of the disease, has been 
described. (Randolph.) 

Symptoms. — After a few days of slight ciliary congestion and 
watering, a faint cloudiness appears, usually, but not always, 
near the centre of the cornea. The spots of haze, if carefully ex- 
amined, will be found to be interstitial opacities, that is, within 
the structure of the cornea itself, and not on cither surface. 

In two or three weeks they spread until the whole cornea is 
invested with a diffuse haziness, veiling or completely hiding the 
iris except, perhaps, through a narrow rim at the margin of the 
cornea. The steamy surface has often been compared to ground 
glass. Careful inspection will reveal that the opacity is not uni- 



DISEASES OF THE CORNEA. '285 

form, luit contains saturated whiter spots scattered through it, 
which have been described as "centres of the disease." There are 
always at this stage ciliary congestion, and some pain and dread 
of light. Bloodvessels derived from the eiliarv vessels are 
thickly set in the layers of the cornea and produce a dull red 
color — "the salmon patch of Hutchinson." These patches may 
be small and crescent-shaped, or large and sector-like. In one 
type (referred to on page 283) the vascularity creeps from above 
and below until the entire cornea is cherry red. 

The subjective symptoms of irritability and photophobia are 
more pronounced in strumous children who are at the same time 
syphilitic. Ulceration rarely occurs, but none the less ulcers of 
discoverable size are sometimes present, and hypopyon and an 
appearance resembling an accumulation of pus in the layers of 
the cornea have been reported. Iritis and the formation of pos- 
terior synechia? are not uncommon, in one form the iritis being 
associated with deposits on the posterior layer of the cornea and 
the formation of anterior synechia?. Inflammation of the ciliary 
region is occasionally encountered ; secondary glaucoma and 
shrinking of the eyeball may follow. 

In the course of time, varying in accordance with the treat- 
ment, the eye begins to clear, usually from the periphery. Perfect 
rec< >very of the transparency must be rare, although the remaining 
haze may be slight. Years after an attack of interstitial kera- 
titis minute vessels, nearly straight, branching at acute angles 
and short bends, may be detected in the cornea. These appear- 
ances have been especially described by Nettleship and Hirsch- 
berg, the latter observer stating that the vessel formation never 
subsides entirely, and he has seen this condition, with the aid of 
a corneal loup, thirteen years after an attack. 

In addition to the complication of iritis and inflammation of 
the ciliary body, more or less retinitis is very apt to be present, 
sometime-; not detected until after the clearing up of the cornea. 
Disseminated choroiditis, and even optic neuritis and retinal 
b( nil >rrliage have also been reported. The presence of the vessels 
and the deposits in the retina and choroid after the disease has 
subsided may be utilized for the diagnosis of inherited syphilis. 

The subjects of typical forms of this disease often present a 



286 



DISEASES OF THE EYE. 



remarkable combination of physical defects. The dwarfed stature, 
the coarse flabby skin, the sunken nasal bridge, the scars at the 
angle of the mouth and also of the nose, the mal-formed perma- 



Fig. 96. 




Vessel formation in the cornea after interstitial keratitis. (Hirschberg.) 

nent teeth, in which the central incisors have vertically notched 
edges (Hutchinson's teeth) 1 indelibly stamp the inheritance of the 
patient. This character of teeth is present in between twenty and 
thirty per cent, of the cases. Indeed, it has been seen as fre- 
quently as thirty-one times in forty-eight cases. The presence 
of deafness, cicatrices in the pharynx, chronic periostitis of the 
tibia, synovitis of the knee-joint (symmetrical or unilateral), and 
indurated lymphatic glands further emphasize the syphilitic taint. 



1 Dr. Harrison Allen, writing concerning " Hutchinson's teeth," says : 
"When the term ' Hutchinson's teeth' is used by clinical writers, a definite 
shape is at once presented to the mind. A disposition exists for the lateral 
incisor teeth of the upper jaw to become pegged, and for the central incisor teeth 
of the same jaw to be slightly convex at the sides and to be deeply emarginate 
(forming a crescent notch) on the free cutting surface. The molars of both 
the upper and lower jaw are often much swollen as their crowns lie in con- 
tact with the gum ; the stunted cusps are seen rising abruptly and irregu- 
larly from the grinding surface. The prevalent views concerning the sig- 
nificance of such teeth are, in the first place, that they result from the poison 
of syphilis acting on the tissues before the birth of the child. Mimetic forms 
may take their origin during an attack of scarlet fever at a time when the 
teetli are not yet perfectly developed." This author describes cases in which 
it appears that Hutchinson's teeth, or allied deformation, may occur in a 
child in whom all the evidence of syphilitic taint or all lesions from scarlet 
fever are wanting;. 



DISEASES OF THE CORN I. A. 



287 



Diagnosis. — The course is usually quite typical and the asso- 
ciated symptoms characteristic. The tension of the eyeball and 



Fig. 97. 




From a photograph of a patient in the Children's Hospital, the subject of inherited 
syphilis and interstitial keratitis. 

the age of the patient in most instances help to exclude pri- 
mary glaucoma, while the history and character of the inflamma- 
tion differentiate it from old corneal maculas and from the diffuse 



288 DISEASES OF THE EYE. 

infiltration of the cornea which is sometimes seen as the result 
of injury. 

The presence of the minute straight vessels is good evidence 
of former interstitial keratitis. These vessels must be distin- 
guished from those which remain after pannus from granular 
lids. According to Hirschberg, in the latter condition they are 
more superficial and pass into anterior conjunctival vessels. 
There are well-formed anastomoses, the broader veins are accom- 
panied by finer arteries, and there are peculiar ramifications of 
the small deep vessels. The vessels seen in corneal scars after 
ulceration are confined to these cicatrices. The rest of the cornea 
is free. 

Certain atypical cases of interstitial keratitis have been de- 
scribed, namely, forms in which the opacities are stripe-like; 
others in which they are ring-like; others presenting the appear- 
ance of pus in the layers of the cornea, the so-called abscess forms ; 
others in which there is a combination of interstitial keratitis and 
keratitis punctata, and that form which is spoken of as central 
annular interstitial keratitis, especially described by Vossius, 
and usually seen in individuals under the age of twenty, and for 
which a definite cause has not been found. The variety which 
begins as a marginal vascular keratitis has been described. 

Prognosis. — From six to eighteen months are usually con- 
sumed in the development of the various stages of the disease. 
The second eye is almost certain to be attacked in from a few 
weeks to two months. In rare instances, the interval is many 
months, even a year ; it may be delayed from five to six years. 
The patient or his friends must be warned of this fact. 

A return to perfect transparency is unusual. The vessel for- 
mation in the cornea probably never subsides entirely, but even 
long-continued opacity- in the course of time may markedly 
lessen, and reasonable vision be restored. The occasional onset 
of deep-seated inflammation of the ciliary region, and the fact 
that after the cornea has cleared, evidences of former choroiditis, 
retinitis or disease of the optic disc, with glaucomatous cupping, 
may be discovered, must not be forgotten in rendering a prognosis. 

Relapses are frequent, not only of the corneal disease, but of 
the complications found in the iris and retina. It has been 



DISEASES OF THE CORNEA. 289 

taught by some observers that the disorder is more severe now 
than in former times. 

Treatment. — All irritating applications are harmful. Atro- 
pine to maintain mydriasis, prevent iritis, and allay inflammation, 
should be systematically employed. If the irritation is great, this 
drug may be cautiously combined with cocaine. Any high grade 
of inflammation calls for the frequent use of hot fomentations, and 
tenderness in the ciliary region will be relieved by a leech applied 
to the temple. The eyes may be protected from dust and light 
by goggles or a dark shade. 

» © ©© 

The best general medication is a long-continued course of mer- 

© © 

cury. Certainly in children, and probably in all instances, the 
most satisfactory method of administration in the earlier stages 
is by inunctions, one drachm of the ointment rubbed into the 
skin once or twice a day according to circumstances. It is a 
good plan to order the mercurial ointment to be put up in one 
drachm masses, thus securing the inunction of a definite quan- 
tity. The usual precautions in regard to changing the spots for 
the rubbings are to be observed. Whenever slight tenderness of 
the gums is apparent, the remedy should be discontinued, a 
chlorate-of-potash mouth-wash should be ordered, and the patient 
put upon a course of iodide of potassium. Subconjunctival injec- 
tions of bichloride of mercury have been advocated, but in the 
author's experience have proved an unsatisfactory method of 
administering mercury in this disease. 

During the administration of the inunction, cod-liver oil may 
be exhibited ; later, bichloride of mercury is a valuable remedy, 
and, as many of the patients are anaemic, this is advantageously 
combined with the tincture of the chloride of iron. Suspicion of 
malaria calls for quinine and arsenic, and in any event they are 
Dseful adjuvants. If rheumatism or rachitis is present, the sali- 
cylates and phosphates are worthy of trial. 

When all irritation has subsided, clearing of the remaining 
opacity is facilitated by the use of a salve of the yellow oxide 
of mercury, together with massage of the cornea, or by the local 
use of a solution of iodide of potassium. Iridectomy, if the ten- 
sion rises and glaucoma threatens, may be necessary; it is evident 
19 



290 DISEASES OF THE EYE. 

that It should be employed for new pupil when stubborn central 
opacity remains. 

A courseof tonic treatment, nourishing diet, exercise, and health- 
ful surroundings are necessary ; in short, all measures are indicated 
which elevate the standard of the patient's general health. Some 
surgeons recommend that mercury be given in the form of hypoder- 
mic injections. An experience with this plan of treatment has not 
caused the author to abandon the older methods of administration. 

Keratitis Punctata. — This affection is almost always secondary 
to disease of the iris, ciliary body, choroid or vitreous, and is 
characterized by a precipitate of opaque dots, generally arranged 
in a triangular manner, upon the posterior elastic lamina of the 
cornea (Descemet's membrane — hence also called Deseemetitis). 
The overlying cornea is hazy, its surface at times slightly uneven. 

The same name is also applied by some writers to those cases 
in which isolated whitish spots, surrounded by a cloudy area, 
appear in the parenchyma of the cornea. The disease is seen in 
young subjects, and is probably syphilitic in origin. Inflamma- 
tory evidences, the appearance of the white dots in the cornea, 
and later the development of iritis, with more diffuse corneal 
infiltration, characterize the disease. Small dotted deposits of 
lens-matter on the back of the cornea after discission may simu- 
late this aifection. (Fuchs.) The eye, however, is uninflamed. 

Iodide of potassium aud bichloride of mercury are proper 
internal remedies. A continued atropine mydriasis should be 
maintained, provided the tension does not rise ; later iridectomy 
may be required to check the iritis, or for optical purposes. 

Keratitis Profunda {Central Parenchymatous Infiltration. Cir- 
cumseribed Parenchymatous Keratitis). — This form of keratitis 
is characterized by the formation of a grayish opacity in tin 
deeper layers of the cornea, sometimes without severe irritative 
symptoms and unassociated with ulceration. 

The cuu.se is often not discoverable ; sometimes cold, rheuma- 
tism, malaria, and injury apparently originate the disorder. 

The following is Fuchs's description of this disease : The gray 
opacity, usually in the centre, is covered by the superficial cor- 
neal layers which are hazy and stippled, but not absorbed. 
Close examination (with a loupe) of the corneal opacity resolves 



DISEASES OF THE CORNEA. 291 

this into individual points, spots, or gray interlacing stripes. 
The deposit slowly absorbs, without ulceration, and commonly 
with only slight vessel formation and leaves the cornea clear, or 
permanent opacity may remain. Symptoms of inflammation may 

or may not be present ; there is hypersemia of the iris. The 
duration of the disease is from one to two months. 

The treatment requires atropine, dark glasses, and later, yellow- 
oxide or similar salve to aid resolution. The constitutional 
treatment is governed by the probable cause. 

Among the more uncommon forms of corneal inflammation 
the following may be mentioned : — 

Keratitis Superficialis Punctata (Keratitis subepithdialis cen- 
tralis. Keratitis maculosa, Nodvli cornea?, Relapsing Herpes 
cornea:). — This disease, which probably is akin to the herpes- 
like corneal inflammations, appears under several forms (just as 
it has been described under several names), either different types 
of the same disorder, or closely analogous manifestations. 

Generally it begins with the symptoms of a sharp conjunctivitis 
in which the secretion is watery, while at the same time there is 
catarrhal disease of the respiratory tract. In two or three days 
numerous small punctiform or linear spots appear, not imme- 
diately beneath the epithelium, but below Bowman's membrane. 
The overlying cornea is slightly hazy and the epithelium 
above the spots a little elevated, the foci being more numerous 
near the centre of the cornea than at the periphery. The cornea 
intervening between the spots is somewhat hazy and contains 
small points and gray lines radiating hither and thither, com- 
parable to the fine fissures in ice. The disease is tedious and 
may last for months. It occurs in young individuals, usually is 
bilateral, and is unaccompanied by loss of epithelium, ulcers, iritis, 
or hypopyon. 

Stellwag finds the foci of large size, most commonly in the 
periphery, that the disease always begins with pain in the 
brow, and that the iris may be involved (nummular keratitis). 
It is analogous to interstitial forms of keratitis. In his cases 
the duration was much shorter, cure having been effected in 
two weeks. 



292 DISEASES OF THE EYE. 

The anatomical nature of the spots is uncertain ; probably 
they are enlarged and opaque corneal corpuscles, or lymph spaces 
filled with opaque matter. The cause of the disorder is unknown 
(tropho-neurosis is suggested), except that it is connected with 
catarrhal affections of the upper air passages. It is analogous 
to herpes, but differs from it in the absence of vesicle formation 
and herpes of the face, its bilateral character, and the great num- 
ber of corneal spots or foci. 

The treatment should be directed to the mucous membrane of 
the naso-pharynx. Locally, during the state of irritation, atropine 
is indicated and later yellow-oxide salve. Full doses of quinine 
would seem to be called for, and it has been recommended to 
use the constant current along the region of the distribution of 
the supraorbital nerve. 

Keratitis Marginalis. — Under this name (which is here used 
in a sense quite different from that employed on page 260), 
Fuchs has described a rare form of keratitis in which a yellow- 
ish-gray zone of opacity, immediately joining the sclera, pushes 
into the clear cornea accompanied by severe inflammatory symp- 
toms, and occupies about one-half of the corneal circumference. 
The vessels of the limbus cover the opacity ; in several weeks 
these and the inflammatory symptoms subside, leaving a rim of 
infiltration somewhat like an arcus senilis, save only that it joins 
the sclera directly and is not separated from it by a stripe of 
clear cornea. The disorder is unaccompanied by ulceration. 

It resembles the angular corneal opacity which appears in con- 
nection with scleritis, and which is known as sclerotizixy keratitis 
(see page 303), but differs from it in the absence of any preced- 
ing scleritis. The disorder occurs in elderly subjects. 

Riband-like Keratitis (Primary Opacity of the Cornea, Trans- 
verse Calcareous Film of the Cornea, Keratitis trophica) appears, 
as pointed out by Nettlcship, in two forms. 

In the one, usually in elderly people, the exposed part of the 
cornea is invaded in a transverse direction by a smooth subepi- 
thelial opacity, oval in shape, which can be chipped off, and is 
composed of an incrustation of lime salts. There is no ulcera- 
tion, and no change in the overlying epithelium. The opacity 



DISEASES OF THE CORNEA. 293 

is sharply limited, and the remainder of the cornea is clear. The 
disorder almost invariably is symmetrical, occurs in men, and is 
situated upon the exposed cornea. A margin of the cornea 
at each end is free. Gout and excess of uric acid in the blood 
have been suggested as constitutional causes, a suggestion 
strengthened by the occasional occurrence of insidious iritis, 
glaucoma, and hemorrhagic retinitis. It may be mistaken for 
the opacity which occurs from the injudicious use of salts of 

lead. 

In the other type of the affection, a horizontal band of opacity, 
grayish-brown in color, crosses the cornese of eyes which have 
long been blind from irido-cyclitis, sympathetic ophthalmia, and 
glaucoma. Here the stripe is less uniform, less sharply defined, 
and consists of a roughened transverse opacity. The calcareous 
nature of the other type may be wanting. As it occurs in the 
lower third of the cornea, or that part exposed when the eye is 
rolled up, and in an eye with impaired nutrition, the affection has 
been considered trophic in its nature. 

Arcus Senilis (Geronto.ron), or a circle of fatty degeneration 
just within the margin of the cornea, is, as its name implies, 
almost invariably found in old persons. A true arcus is always 
separated from the adjacent sclera by a thin stripe of clear cor- 
nea. Occasionally a genuine example of this affection appears 
to have been noted in children (Hansell). Instances which have 
been reported at birth must not be confounded with an arciform 
opacity, the result of ulceration. 

The affection requires no treatment, and its presence appears 
not to interfere with the healing of wounds ; for example, in 
cataract incision. 

Conical Cornea ( Keratoconus). — This consists of a cone-shaped 
bulging forward of the cornea, and is rarely congenital. It is 
mostly seen in women, and usually does not develop until after 
the age of fifteen. Exhausting illness, menstrual disturbance, 
and especially chronic dyspepsia, have been observed to be asso- 
ciated with the development of conical cornea, the immediate 
cause being a disturbance in the relation of the intraocular pres- 
sure to the resistance of the cornea. 




294 DISEASES OF THE EYE. 

The cone is transparent in most instances ; occasionally its 
Fig. 98. apex is slightly opaque. The bulging 

slowly progresses, but does not rupture 
nor ulcerate. After years it comes to 
a standstill. One or both eyes may 
be involved, commonly the latter, the 
second eye being affected some time 
after its fellow. The eye becomes 
myopic and highly astigmatic. Slight 
forms of conical cornea may be overlooked, unless the shadow- 
test is employed and the characteristic reflections observed. 

Treatment. — Although no form of glass, or no optical appa- 
ratus may avail in advanced cases, a careful trial should always 
be made with sphero-cylindrical combinations, and in some 
instances their employment in unusual combinations will mark- 
edly improve visual acuity. It is always wise to use eserine 
(gr. |-f3j) for several weeks before attempting the correction 
(Wallace). 

If the apex of the cone appears to be thinning, a weak solu- 
tion of sulphate of eserine and a compressing bandage are indi- 
cated. 

In advanced cases an operation is advised, having for its ob- 
ject the substitution of a contracting cicatrix for the tissue at the 
apex of the coue, which shall diminish the excessive curvature. 
Several plans are suggested : («) Cutting off a small, superficial 
flap and subsequently cauterizing the surface, associated with 
repeated paracentesis of the cornea, and later a small iridectomy 
for optical purposes; (6) cutting off the flap and drawing the 
edges of the wound together with delicate sutures ; (c) cutting 
from the apex of the cone a small disc, with a trephine ; (d) 
multiple punctures with fine needles; (e) obtaining the desired 
loss of substance by the application of a galvano-cautery. As 
the resulting scar is directly central, an iridectomy for optical 
purposes will usually be required, an operation indicated under 
any circumstances if the tension rises. 

Buphthalmos (iTydrophthahnos congenitua, Keraio-globus, Me- 
galocornea, Glaucoma oongenitum). — In this affection there is 
slow but progressive enlargement of the eye in all its diameters; 



DISEASES OF THE CORNEA. 295 

tlif cornea is flatttened, the sclera thinned, and the anterior 
chamber deepened ; the tension is raised. In the course of time 
the cornea may become cloudy (kerato-globus turbidus), although 
this is not always the ease (kerato-globus peUuddus.) 

The affection appears at birth or shortly afterwards, and its 
incipient stages are believed to be intra-uterine. The precise 
cause is not accurately determined. It has been ascribed to an 
intra-uterine irido-keratitis with increased intraocular tension; 
in other words, a form of congenital glaucoma. 

The prognosis is unfavorable; the affection usually progresses 
to blindness. Iridectomy has been practised -with poor success; 
some favorable results with sclerotomy have been reported. Ese- 
rine or pilocarpine should be tried. 

Injuries of the Cornea. Traumatic Keratitis. — These com- 
prise ( 1 ) foreign bodies ; (2) erosions ; (3) wounds ; and (4) bums 
and sealds. 

Fort ir/n bodies, as particles of sand, fine splinters of iron and 
bits of emory, may lodge either upon the epithelium or become 
imbedded in the substance of the cornea. If they are sharp, 
like a splinter of iron, or small thorn from a chestnut-burr, they 
may partially penetrate the membrane. 

The pain of even a minute foreign body is considerable ; the 
eye waters and grows red, and the source of irritation is com- 
monly referred to the under surface of the upper lid, although 
the intruder may be directly upon the centre of the cornea. 

To remove an imbedded foreign body a drop of a four per 
cent, solution of cocaine is instilled, the upper and lower lids are 
held apart with the thumb and forefinger of the surgeon's hand, 
while with the right hand he takes a fine needle, or a spud, and 
lift- the body from its position with as little injury as possible to 
the cornea. Sometimes, if the situation is deep, several digging 
motions with the instrument will be recpiired to dislodge the 
-ul istance. The area should afterwards be inspected by means 
of a two-inch lens and oblique illumination. In any case in 
which the operator is not sure that he has removed the foreign 
substance he may resort to the fluorescin-method described on 
page 02. If the substance has been iron or emery, a small, 



296 DISEASES OF THE EYE. 

rust-like spot will often remain. Powder grain* may be removed 
by touching them with a fine galvano-cautery point (E. Jackson). 

If the spicule has partially penetrated, it may be necessary to 
pass abroad needle through the cornea behind it to secure a sur- 
face against which to work, and to prevent the manipulations 
from pushing it entirely through the cornea and into the anterior 
chamber. 

After the removal of the foreign body, the resulting irritation 
may be allayed by a drop of atropine; the use of a bandage for a 
few days will facilitate the healing of the ulcer. Disinfection of 
the conjunctival cul-de-sac with a bichloride lotion, and steriliza- 
tion of the spud should be secured. 

Erosions. — A superficial loss of epithelium caused by the con- 
tact of a sharp body, like a finger nail, in itself may be insigni- 
ficant, but may lead through septic infection to a severe ulcera- 
tion, particularly if the injured eye is exposed to the discharge 
from an inflamed lachrvmo-nasal duct. 

The heatment consists of the instillation of an antiseptic lotion, 
for example, bichloride of mercury (1-8000) and the use of 
atropine, with a compressing bandage to immobilize the lids 
until healing takes place, provided no septic discharge is present. 

A number of cases, in which violent neuralgic pain has followed 
an insignificant scratch of the cornea, have been reported ; this 
condition is called traumatic keratalgia. The attacks of pain 
recur again and again and may last for years. The affection 
probably is due to a neuritis of a corneal nerve filament. 

The remarkable affection, relapsing erosions, has been referred 
to, and belongs to the types of corneal disease associated with the 
formation of vesicles. 

Wounds of the cornea naturally divide themselves into non- 
penetrating and penetrating, and differ in character according to 
the implement which has inflicted them. 

Nbn-penetraiing wounds partake of the nature of erosions, and, 
like them, may be in themselves of minor importance, bui may 
result in violent ulcers through microbic infection. 

The treatment already described is applicable. 

A penetrating wound allows the escape of the aqueous and 
renders incarceration of the iris liable, with all the possibilities 



DISEASES OF THE CORNEA. 297 

described iu connection with perforating ulcers. The wound 
may injure the len> and cause traumatic cataract, or involve the 
ciliary region and cause sympathetic inflammation. 

After a perforating wound of the cornea, the eye should be 
thoroughly disinfected; the iris, if prolapsed, replaced if possible, 
and eserine or atropine instilled according to the situation of the 
injury. If replacement is not possible, the prolapsed portion 
should be seized with iris forceps and excised, after the manner 
of performing an iridectomy. In either event the subsequent 
treatment requires rest, disinfection of the conjunctival cul-de-sac, 
and a carefully applied antiseptic compressing bandage. 

The tendency to traumatic iritis may be combated by the 
frequent use of cold compresses. Inflammatory reaction would 
call for a leech to the temple. In severe corneal wounds, invol- 
ving the iris, lens, and ciliary body, the question of enucleation 
or evisceration must be decided. 

Bin- rts and Scalds are produced by the contact of acids, lime, 
molten metal, and hot water or steam, and the general manage- 
ment of such cases does not differ from that of similar accidents 
to the conjunctiva which necessarily is involved. 

Sometimes the burn may be superficial and the whole surface- 
epithelium be changed into a white scum, which presents a most 
alarming appearance. The destroyed tissue, however, is speedily 
replaced by a new layer of epithelium. Burns with slaking lime 
are those most liable to result in disastrous consequences. 

All the various forms of corneal injury cause more or less 
severe inflammations properly classed under the general term 
trim math: keratitis, and possess in greater or less degree the cardi- 
nal symptoms of keratitis — pain, lachrymation, photophobia, and 
disturbance of vision. 

Tumors of the Cornea. — These are very rare and include 
the growths which develop from the epithelium — epithelioma, or 
invade it by extension from the neighboring tissues — sarcoma. 
A few instances of fibroma, papilloma, and primary sarcoma 
have been reported. 

Dermoid tumor is a congenital growth, and sometimes is asso- 
ciated with other anomalies of the lid and eyes. It occurs as a 
firm hemispherical, yellowish-white growth, lying partly upon 



298 DISEASES OF THE EYE. 

the cornea and partly upon the conjunctiva. The apex, often 
paler than the rest of the growth, is covered with short hairs. 
These, however, occasionally grow to an unusual length and have 
been seen protruding through the iissure of the lids and hanging 
down upon the cheeks. If undisturbed, the tumor may slowly 
enlarge, and has been reported to have attained the size of a wal- 
nut. Bilateral dermoids have been recorded. 

These dermoids have been ascribed to the remains of amniotic 
adhesions ; but also to the coalescence of the lids in such a way 
that at the moment of separation one lid attracts to itself a portion 
of the other. Microscopically, the growth represents the struc- 
ture of the skin and its appendages. The presence of striped 

muscle fibre and acinous glands, 
■ "• analogous to those in the con- 

junctiva, has been described in 
dermoid of the caruncle. 

Congenital Anomalies of the 
Cornea. — JlicrojjJithalmos is that 
condition in which the entire 
eye remains in a more or less 
rudimentary state, and in which 

the cornea is too small in all its 
Dermoid of the cornea. From a pa- 
tient in the Philadelphia Hospital, diameters. Pure cases of mi- 
en >phthalmos, accordingto Manz, 
are very rare ; usually one or other of the component portions 
of the globe is wanting. Numerous theories have been expressed 
in regard to the etiology, — retarded growth of the cerebellum 
(Kundrat), incomplete closure of the foetal ocular cleft (Arlt), 
feetal illness in orbita ("Wedl and Boch), intrauterine sclero- 
choroi-retinitis (Deutschmann). The affection has also been 
ascribed to the influence of heredity. 

Megalophthalmos lias been described on page 294. 

Sclerophthalmia or Sclerosis is that condition in which the opa- 
city of the sclerotic encroaches upon the cornea in such a manner 
that only the central portion remains transparent. It is due to 
an imperfect differentiation of the cornea and sclera at an early 
period of foetal life. It may be symmetrical, and affect only the 
upper half of the cornea. 




DISK ASKS OF THE CORNEA, 299 

< bngenital opacities of the cornea are seen in the form of milky 
Bpots which may clear up in later life, or as dense leucomas. 
They arc due cither to intra-uterine inflammation, or to an arrest 
of development. 

< bngenital staphyloma of the cornea appears in the form of a 
true staphyloma, and is a rare affection. The abnormality de- 
pends not so much upon a malformation, or an arrest of develop- 
ment, as upon a foetal inflammation which, according to Pincus, 
takes place in the second half of foetal life. Heredity probably 
plays some role in this and similar affections of the cornea. Con- 
genital staphyloma of the cornea associated with dermoid forma- 
tion has been reported. 

Filamentous Keratitis is an unusual condition characterized 
by the development of small threads of tissue from wounds 
(traumatic f. keratitis), or herpetic spots (spontaneous f. keratitis) 
cm the cornea. The tags have a bulbous extremity, are often 
twisted like a rope, and are attached to the cornea by a pedicle. 
Their appearances must be studied with a loupe or microscope. 
They represent an active proliferation of epithelium. They may 
speedily disappear, or persist, or recur after removal. 

Elood-Staining of the Cornea. — This phenomenon has been 
observed in cases of hyphemia and increased intraocular tension. 
The cornea assumes a smoky or rust-colored tint, except at its 
periphery, the clear portion being sharply separated from the 
cloudy ana, which, however, is usually more pronounced in its 
centre. The appearances closely resemble those of an amber- 
colored lens dislocated into the anterior chamber. With the 
microscope numerous granules (probably hsematoidin) are found 
deposited in the substantia propria, which, according to Griffith, 
have entered the corneal tissues by endosmosis in a state of solu- 
tion. The lesions have been studied by T. Collins, Vossius, 
Weeks, and J. Griffith. 



300 DISEASES OF THE EYE. 



CHAPTER VIII. 

DISEASES OF THE SCLERA. 

The sclera, constituting four-fifths of the covering of the globe 
of the eye, and being in intimate relationship by its under surface 
with the choroid and ciliary body, is subject to inflammations 
peculiar to itself, and to changes indicative of disease of these 
subjacent structures. Its close connection with the cornea asso- 
ciates the latter membrane in some phases of its diseases, and its 
union with the iris through the pectinate ligament establishes 
an anatomical connection, just as there often is a pathological 
relation. The overlying bulbar conjunctiva necessarily partici- 
pates in scleral inflammation. 

The inflammations affect (1) the episcleral tissue (episcleritis) ; 
and (2) the sclera itself (scleritis), and hence are superficial or deep. 
They further are acute or chronic, diffuse or circumscribed. 

Episcleritis occurs in the form of small, dusky red, sub-con- 
junctival swellings, which usually appear in the ciliary region on 
the temporal side of the cornea, though patches may occur in 
any portion of the zone. 

The conjunctival vessels over the patch are coarsely injected, 
and movable with the somewhat ^edematous conjunctiva. The 
episcleral vessels show a dusky congestion which is immovable. 
The elevation is back-shaped ; sometimes tender to pressure and 
sometimes not, and there may or may not be much irritation 
and pain. In some cases of thickened phlyctenular disease of the 
corneal margin it is difficult to decide between this affection and 
episcleritis ; what appears to be a patch of the latter may develop 
into the former. 

The disease runs a subacute course, reaching its height in about 
three weeks, then gradually disappears and leaves a somewhat 
dull area of discoloration, marking its former position. Relapses 
are frequent, both at the original seat, or in new spots on the sclera, 



DISEASES OF THE SCLERA. 301 

and these recurrences may happen again and again lor months 
and even years. 

( \ use. — It is said to be more common in men than in women. 
(Nettleship.) Patches of episcleritis of the character described 
occur in the eyes of those who are much exposed to the weather. 
In other cases superficial scleritis is caused by rheumatism, 
scrofula, menstrual derangements, and also appears without 
cause. It is probable that a patch of episcleral congestion may 
be maintained by insufficiency of the ocular muscle inserted in 
the neighborhood of its location. 

In this form of superficial scleritis the 2 )ro 9 n °8is is good so far 
as sight is concerned, because deeper and adjacent structures are 
uninvolved, but unfavorable on account of the recurrences. 

Treatment. — This consists in the use of atropine to allay pain 
and prevent any tendency to iritis, warm antiseptic colly ria, 
and hot compresses. In the chronic types eserine and pilo- 
carpine have a beneficial influence, provided no iritis is present. 
Eserine may be employed in the strength of ^— J of a grain to 
the ounce ; several drops three times a day, — stronger solutions 
give rise to pain. Massage with a salve of the yellow oxide of mer- 
cury is very useful in chronic cases, and it has been recommended 
t<> scarify the tumefaction, scrape it away with a sharp curette, or 
cauterize it with the actual cautery. Internally, salicylic acid 
and iodide of potash are needed in rheumatic cases, and good 
results follow diaphoresis either with jaborandi or the Turkish 
bath. Menstrual and uterine disorders must be rectified. Any 
error of refraction or anomaly of the external eye muscles should 
be corrected. 

Scleritis may appear in the form of a diffuse bluish-red injection, 
occupying the entire exposed portion of the sclera, very painful, 
unattended with secretion, save some increase in lachrymation, 
and liable to be mistaken for conjunctivitis or iritis; or in the 
form of circumscribed patches, of violaceous tint, situated in the 
ciliarv region and somewhat resembling in appearance the forms 
of superficial or episcleral elevations just described, being, how- 
ever, less sharply defined, so that the whole zone maybe involved, 
but in unequal degree. The chief distinction between the 
superficial and deep forms of scleral inflammation is the almost 



302 DISEASES OF THE EYE. 

invariable tendency of the latter to affect other portions of the 
eye. 

Cause. — The causes of deep scleritis are exposure to cold, rheu- 
matism, gout, scrofula, vaso-motor changes, and disturbances of 
the sexual apparatus, especially anomalies of menstruation. Syph- 
ilis may form the so-called gummatous scleritis, in which the 
patches are yellowish-brown and translucent; and gonorrhoea, 
when this is associated with synovitis, may also cause the dis- 
order. Finally, types of scleritis (sclero-keratitis) unassociated 
with any definite cause or diathesis, are seen in young and mid- 
dle-aged subjects, most commonly women, whose nutrition is de- 
pressed, and who may or may not have a scrofulous disposition 
or inheritance. 

Deep scleritis usually attacks both eyes, runs a chronic course, 
and may affect the iris (leading to closure of the pupil), ciliary 
body, choroid, vitreous (causing opacities), and the cornea. In 
prolonged cases of the disease dark scars remain after absorption 
of the products of the inflammation, which are unable to resist 
the intraocular pressure, and form elevations (ectasia sclerse). 
Sometimes the whole anterior portion of the sclera becomes 
bluish or slaty-colored, is misshapen and elongated, and the 
cornea, which appears small, is poorly differentiated from it on 
account of the haziness of its margins. 

Sclero-kerato-iritis (Scrofulous Scleritis, Anterior Choroiditis). 
— This name is applied to the complicated scleritis referred to 
in the previous paragraph, and is characterized by chronieity, 
relapses, and involvement of the cornea and iris. 

Beginning with a deep scleritis of the ciliary zone, the adjacent 
cornea becomes opaque, and sometimes ulcerates ; the iris is in- 
flamed, posterior synechia form, and pain and congestion may be 
severe. After weeks the symptoms subside, the characteristic dis- 
colored area marks the former scleral disease, and haziness in the 
cornea indicates the seat of previous inflammation in this mem- 
brane. Then relapse takes place, with fresh scleritis, new corneal 
involvement, renewed iritis, or irido-choroiditis, and vitreous 
changes, and so on, until after many months, it may be, the dis- 
ease comes to an end, leaving the sclera discolored and bulged, 
the cornea covered with patchlike opacities, the iris bound down 



DISEASES OF THE SCLERA. 303 

with adhesions, the vitreous filled with opacities, and the eye 
practically deprived of vision. 

Sderotising keratitis, referred to on page 292, is the name ap- 
plied to a patch of opacity in the deeper corneal layers, usually 
triangular in shape, with its base towards the patch of scleritis 
which is its origin. After the cure of the scleritis, a white or 
yellowish-white opacity remains directly in contact with the 
sclera by its margin. Instead of a single patch of this char- 
acter, several small triangular areas may arise in the circum- 
ference of the cornea as the result of scleritis. 

Treatment. — The treatment of scleritis and sclero-kerato- 
iritis depends upon the type and stage of the disease, and the 
presence or absence of definite cause. It resembles that already 
described with episcleritis. Locally, atropine, hot compresses, 
cocaine and boric acid lotiou, and in painful cases leeches to the 
temple, are suitable. Pilocarpine is valuable if iritis is not 
present. The eyes should be carefully protected with goggles. 
After the subsidence of acute symptoms, massage may be tried. 
The use of the actual cautery has beeu mentioned. 

In rheumatic cases, salol, the salicylates, the alkalies and iodide 
of potash are the most available remedies ; in gout, carefully 
regulated diet, mineral waters — Buffalo, Poland, etc. — citrate of 
lithium, colchicum, especially in the form of colchicin, and 
change of climate are useful. In scrofulous cases, cod-liver oil, 
iodine, iron, and sweats with pilocarpine (gr. y 1 ^ hypodermically), 
or 15-30 minims of the fluid extract of jaborandi, are indicated. 
The diaphoretic measures are proper in any case, other things 
being equal. In syphilis, bichloride of mercury, and, if the 
nutrition permits, inunctions of mercurial ointment, are effica- 
cious. Indeed, mercury is generally advantageous as a means 
of altering the nutrition of the part and preventing exudation 
into the uveal tract. Disorders of menstruation should always be 
corrected. Finally, in subjects with depressed nutrition, quinine, 
arsenic, and a general tonic regimen are required. 

It is not always possible to distinguish between episcleritis 
and scleritis, unless the latter term be applied solely to those 
cases which involve structures other than the sclera itself; neither 
is it always possible in the early stages to say whether or not a 



304" DISEASES OF THE EYE. 

patch of episcleral inflammation will develop into a serious type 
of the malady, or be temporary and abortive. 

Staphyloma of the Sclera has been divided by systematic 
writers into anterior, equatorial, and posterior staphyloma, ac- 
cording to the situation of the lesion. The last is not visible to 
the naked eye, but, by the findings of the ophthalmoscope, may 
be inferred to exist in a highly myopic eye (see page 354). 

It is evident that all bulging of the scleral depends upon a dis- 
turbance between the resistance of the sclera and the intraocular 
tension, but it is not evident in all cases whether the process 
which originated the trouble began in the underlying tissue or 
in the scleral structure itself. There may be a general enlarge- 
ment of the scleral coat, as is seen in buphthalmos (page 294) ; or 
one or more darkly tinted swellings in the ciliary region may 
arise, one sometimes occurring in advance of each rectus tendon ; 
or, finally, the staphylomatous swelling may exist at the equator 
in the region of the vena vorticosa. 

The following causes may originate scleral staphyloma : Chronic 
glaucoma, old kerato-iritis and closure of the pupil, inflammation 
of the ciliary body, thinning of the scleral coat by repeated at- 
tacks of inflammation, tumors, and wounds closed by non-resist- 
ing scars. 

Treatment. — A single scleral staphyloma may not destroy 
vision. If the intraocular tension is increased, an iridectomy is 
indicated. If the eye is useless, enucleation may be necessary. 

Abscess and Ulcers of the Sclera are exceedingly uncommon, 
as the products of scleral inflammation rarely go on to suppura- 
tion or ulceration. Abscess in the scleral tissue may result from 
an infected wound, and has been seen in connection with certain 
specific and contagious diseases, e. g., glanders. 

Ulcer of the episcleral tissue has been described with scrofula. 
A tumor, gumma, or tubercle of another region of the eye may 
break down and ulcerate into the sclera. 

Tumors of the Sclera are rare growths. The following have 
been seen : Fibroma, sarcoma, enchondroma, and osteoma. 

The tissue of the sclera may be involved in a growth having 
its origin in a neighboring structure, e.g., melano-sarcoma of the 
ciliary body. Small primary scleral growths may be dissected 



DISEASES OP THE SCLERA. 305 

from their beds and the wound closed with conjunctival 
sutures. 

Injuries of the Sclera. — Wounds of the sclera may be in- 
flicted with a sharp implement (knife, scissors, broken glass, etc.) 
or foreign body (chip of iron or steel, bullet, etc.), or they may 
result from a blow, causing rupture of the sclera, usually found 
3 mm. from, and concentric with, the corneal margin (T. Collins). 

If the wound has perforated the sclera, two dangers at once pre- 
sent themselves : loss of a portion of the contents of the globe 
with injury to the inner coats, and the introduction into the eye 
of septic material which will cause destructive inflammation. 

Symptoms. — A perforating wound of the sclera, if sufficiently 
large, causes loss in the tension of the globe, hemorrhage into 
the vitreous, or, it may be, into the anterior chamber, and the ap- 
pearance of dark tissue in the wound, representing, according to 
its situation, portions of the choroid, ciliary body or iris, between 
which a bead of vitreous is likely to present. The diminution 
of intraocular tension may lead to the discovery of a small per- 
forating scleral wound where the rent is obscured by the over- 
lying contused and swollen conjunctiva. Rupture of the sclera 
is commonly associated with grave lesions in other portions of 
the eye — separation of the retina, and extensive tears in the cho- 
roid and iris. 

Prognosis. — This depends upon (a) the extent and situation 
of the wound and amount of escape of vitreous ; (b) the presence 
or absence *of septic material upon the implement or body which 
inflicted the injury; and (c) whether a foreign body has remained 
within the globe. From this it is evident that even a trifling per- 
forating wound, unattended with loss of vitreous or prolapse of 
the inner coats, may be a point of entrance of microbic infection. 

Treatment. — Having determined, from the character of the 
implement, that no foreign body is within the globe, the eye 
should be carefully disinfected with a solution of bichloride of 
mercury (1-5000), and the edges of the wound pencilled with a 
stronger solution of the same drug (1-2000). The overlying 
conjunctiva is then drawn together with several fine sutures, or, 
if the wound is small, these may be omitted. The eye is closed 
with an antiseptic compressing bandage, and the patient is put to 
20 



306 DISEASES OF THE EYE. 

bed. At the end of forty-eight hours the wound may be inspected 
and the dressings renewed. In larger wounds the sutures (sterile 
silk or catgut) may be passed directly through the sclera, care 
being taken to avoid the choroid, although according to Snell 
this is not necessary or advisable, conjunctival sutures being suf- 
ficient ; usually the sutures may be removed at the end of a 
■week, if the healing has progressed favorably. Some surgeons 
advise the introduction of iodoform before the application of the 
bandage. In some instances, in spite of kind healing of the 
scleral wound, there is subsequent detachment of the retina, 
vitreous change, and shrinking of the eyeball ; but apparently 
hopeless cases may be saved by careful antiseptic surgery. 

In the event of a scleral wound being extensive, with much 
loss of vitreous and collapse of the coats, especially if the ciliary 
body is involved and sight practically gone, or if the endeavors 
to remove the foreign body have been unsuccessful, enucleation 
should be performed to avoid the dangers of sympathetic inflam- 
mation in the fellow eye. 

Foreign Bodies. — If the wounding substance has been small, 
e. g., a chip of steel, a splinter of glass, or a bullet, endeavor 
should be made to ascertain whether this has penetrated the 
globe and remained within it, or has passed entirely through the 
eyeball and buried itself in the tissues of the orbit. Foreign 
bodies may be imbedded in any of the structures of the eye and 
are frequently found in the vitreous. If loose they tend to grav- 
itate to the lowest part of the vitreous and rest upon the poste- 
rior part of the ciliary body (T. Collius). According to Leber, 
perforating injuries of the eye with pieces of copper may result 
in purulent inflammation merely by the chemical action of the 
metal ; if microbes are proved to be absent by culture experiments, 
an attempt to remove the body may be made, and, if successful, 
the eye saved, even if inflammation has begun. Foreign bodies 
may be tolerated for long periods of time, with good vision, in 
the background of the eye, but, according to Knapp, can never 
be trusted, unless they are small and the accompanying changes 
trifling; under other circumstances they arc liable to cause de- 
generative inflammation. 

Unfortunately, the bleeding into the vitreous, or anterior 



DISEASES OF THE » LERA. 307 

chamber, is apt to obscure the media to such a degree that oph- 
thalmoscopic examination is not of much service; if the media 
arc clear, this may be the means of detecting the foreign body. 
Usually an attempt at locating this must be made by observing 
the situation of the wound, the probable direction which the body 
took on making its entrance, and by a search for points of tender- 
ness, and a scotoma in the field of vision. 

Having satisfied himself of the presence of a foreign body 
within the globe, the surgeon may attempt to extract it through 
the original wound with delicate, carefully disinfected forceps, 
or through a new wound made in the most favorable situation. 

If the foreign body is known to be of iron or steel, an attempt 
should be made to dislodge it with an electro-magnet intro- 
duced through the entrance wound, or, if the case is not a recent 
one, through a wound made for the purpose. 

Congenital Pigmentation of the Sclera {Melanosis scleroe) 
occurs both in spots and as a more diffuse discoloration. The 
spots are more common in the upper portion, and may be associ- 
ated with pigment changes in the iris and choroid. Pigment 
spots in the sclera have been observed in certain diseases, e. g. f 
Addison's Disease, and sometimes are exactly symmetrical, situ- 
ated near the margin of the cornea. 



308 DISEASES OF THE EYE. 



CHAPTER IX. 

DISEASES OF THE IRIS. 

Congenital Anomalies. — Heterophthalmos, or the condition in 
which the color of one iris is different from that of the other, is 
a peculiarity in most instances without pathological significance. 
It has been referred to on page 63. 

Corectopia, a term applied to an eccentric position of the pupil, 
is not to be confounded with cases of true coloboma of the iris, 
presently to be described. The grade of corectopia may vary 
from a slight increase of the normal eccentric position of the 
pupil below and to the inner side, to those cases in which the 
Avhole pupil is displaced toward the border of the cornea. The 
latter variety is a very unusual phenomenon. This complete 
shifting of the normal position of the pupil has been ascribed 
either to an essential mal-formation, or to the result of a foetal 
iritis. Both eyes may be affected symmetrically, and several 
members of the same family may present the defect. 

Polycoria, or a multiplicity of pupils, is a rare anomaly. The 
abnormal pupil or pupils may be situated in the immediate 
neighborhood of the normal pupil, separated from one another by 
a narrow band of iris-tissue, or the increased number of pupils 
may be the result of crossing strands of persisting pupillary mem- 
brane (Fig. 101). An opening which exists at the ciliary mar- 
gin of the iris has been described, and is probably due to a con- 
gen ital iridodialysis. 

Persistent pupillary membrane results from an incomplete reso- 
lution of the membrane which covers the anterior surface of the 
lens during fetal life, and which usually disappears in the 
seventh month, although it may remain as late as the end of 
intrauterine life, and even in the first month after birth. 

Accurately speaking, it is more proper to regard the pupillary 
membrane as a specialized portion of the capmlo-pupillary 



DISEASES OF THE IRIS. 



309 



covering. The name of pupillary membrane alone is applica- 
ble to those cases in which threads attached to the small circle 
of the iris pass diametrically or cord-wise across the pupil, to 
be inserted elsewhere in the corona. (Fig. lOO.) Usually the 
fibres proceed from the anterior surface of the iris across the 



Fig. 100. 



Fig. 101. 





Persisting pupillary membrane : 1. Pupil contracted ; 
2. Pupil dilated. (Wickerkiewicz.) 



Polycoria. 



pupil, either singly or in groups of three or more strands. 
Sometimes the fibres remain separated ; sometimes they grow 
together in front of the anterior capsule or unite in the form of 
a variously colored plaque, adherent to the capsule of the lens 
(capsulo-pupillary membrane). Persistent pupillary membrane 
is more common in one than in both eyes ; of 68 cases observed 
by Stephenson, 13 were bilateral and 55 unilateral. 

Capsulo-pupillary tags are not infrequently mistaken for the 
synechia? due to iritis ; indeed, the association of the two has 
been observed. No difficulty, however, should arise, because the 
normal action of the pupil is not impeded by the presence of 
these vestigial anomalies. The appearance is not often detected 
until some other disorder calls for an ophthalmoscopic examina- 
tion, because vision is not seriously, or at all, impaired. Oblique 
illumination will readily demonstrate the remains of pupillary 
membrane, and, indeed, is the best method with which to study 
this phenomenon. 

Coloboma of the iris is a fissure of this membrane which in a 
general way resembles an artificial pupil made by iridectomy. 
The anomaly is more frequent in both eyes than in a single eye. 
When the defect is unilateral, the anomaly is usually found on the 



310 DISEASES OF THE EYE. 

left side. The situation of the fissure is almost invariably down- 
ward, or downward and inward. 

The coloboma may extend across the whole iris {complete 
coloboma), or stop at a certain distance from the ciliary margin 
{incomplete coloboma). In addition, the so-called pseudo-coloboma 
is described, which may be looked upon as a form of hetero- 
chromia of the iris, or indicates the last remains of the ocular 
fissure which is tending towards closure, and which appears as a 
small stripe, somewhat granular, and differentiated from the rest 
of the iris by its brighter color. In " bridge coloboma," the 
borders of the cleft are united by a narrow pigmented or color- 
less band of fibres. 

Coloboma of the iris is frequently associated with similar de- 
fects in the choroid, and also with microphthalmos, congenital 
cataract, fissure of the eyelids, lips, and palate. Its probable 
cause is an arrest of development, the result of incomplete closure 
of the choroidal fissure. Much evidence has been brought to 
show hereditary tendency in this defect. 

Irideremia, or congenital absence of the iris, occurs both in a 
partial and complete form. The appearance somewhat resembles 
an eye with complete mydriasis. 

Total congenital irideremia is almost invariably bilateral. 
It is frequently associated with other anomalies of the globe — 
partial or complete cataract, dislocation of the lens, nystagmus, 
strabismus, departures from the normal curvature of the cornea, 
or annular opacities in its periphery. In a majority of instances 
there is a marked hereditary tendency. 

Congenital ectropion of the uvea consists in a round mass of 
dark color projecting from the margin of the pupil, bending 
around to the anterior border of the iris. A similar formation 
is proper to the eye of the horse and is frequently seen in the 
cow. This appearance lias sometimes been described as a papil- 
loma of the iris; it is not, however, a neoplasm, but a congenital 
ectropion of the uvea. 

Cysts, mevi, and atrophies of the iris occur as congenital defects. 

Functional Motor Disorders of the Iris. — Under this heading 
may be mentioned mydriasis, or dilatation of the pupil ; myosis, 
or contraction of the pupil ; hippus, or alternate contraction and 



DISEASES OF THE IRIS. 311 

dilatation of the pupil (see also page 64). Irido-donesis, or 
tremulous iris, or an oscillation of the iris depending upon want 
of support, as, for instance, in dislocation of the lens, although 
not a functional motor disturbance of the iris, is conveniently 
mentioned in this connection. 

Hyperaemia of the Iris is associated with several acute 
affections of the eye, for example, acute trachoma, purulent con- 
junctivitis, keratitis, scleritis, inflammations of the uveal tract 
and traumata, and is a precursor of inflammation. Hence it is 
a symptom rather than a special disease of the iris itself. 

Hyperemia of the iris is recognized by change in color, a blue 
iris becoming greenish, a brown iris, reddish-brown ; by con- 
traction of the pupil, which dilates sluggishly, or not at all, to 
the changes of shade and light, and is slowly affected by a mydri- 
atic, the effects of which are much less permanent than in the 
healthy iris ; and by slight pericorneal injection. 

The treatment consists in the management of the disease which 
has caused the hyperemia, and especially in the instillation of 
atropine. 

Iritis. — Under the general term iritis are included various types 
of inflammation of the iris which may be (a) idiopathic ; (6) 
symptomatic of disorders in other portions of the eye, or of dis- 
ease in the general constitution ; and (c) traumatic. 

Symptoms. — (1) Change in the color of the iris, in addition to 
loss of its natural lustre and obscuration of the characteristic 
striated appearance. 

(2) Pericorneal injection, due to congestion of the non-perfo- 
rating branches of the ciliary vessels (System II.), producing the 
fine pink zone surrounding the cornea known as " ciliary con- 
gestion," or the " circumcorneal zone." In severe cases, there 
may be distension of the posterior conjunctival vessels, and slight 
chemosis of the conjunctiva. 

(3) Myosis, or contraction of the pupil, due partly to hyper- 
sernia, and partly to irritation of the peripheral nerve filaments. 
The reaction of the pupil to the influence of light and mydri- 
atics is diminished or lost. 

(4) The formation of posterior synechias, or inflammatory at- 
tachments between the iris and the capsule of the lens. These 



312 DISEASES OF THE EYE. 

may be suspected when the pupil fails to change its diameter 
under the varying influence of light and shade, and are demon- 
strable by the instillation of a mydriatic, which will produce an 
irregular dilatation of the pupil, certain portions of the pupillary 
margin of the iris being held back by somewhat tongue-shaped 
projections attached to the lens capsule. 

The attachments may vary in size, firmness, and number ; 
being either narrow and thread-like, broad and dense, single or 
multiple, or even extending all around and pinning down the 
margin of the iris in an annular manner. In association with 
the synechia? there may be an exudate of false membrane cover- 
ing the whole pupillary space. 

Fig. 102. 




Various forms of posterior synechia. A. Single attachment. B. Multiple 
attachment forming the so-called " ace-of-clubs" pupil. C. Irregular annular 
attachments (Sichel). 

(5) Irregularities in the surface of the iris, due to local swell- 
ings, accumulations of exudate, or the formation of nodules. 

(6) Haziness of the cornea, or in certain types, deposits upon 
its posterior surface. 

(7) Change in the character of the aqueous humor ; (a) slight 
or considerable turbidity ; (b) pus ; (c) blood ; and (d) occasion- 
ally exudate. 

In addition to the symptoms just detailed there are subjective 
signs more or less peculiar to iritis. 

(1) Pain. — This is situated first in the eyeball and is known 
as "ciliary pain," and second in the brow and temple, sometimes 



DISEASES OF THE IRIS. 313 

quite sharply defined in the distribution of the supraorbital 
nerve, very severe, throbbing and stabbing in character, and with 
marked increase in severity during the night. Occasionally the 
nasal and infraorbital regions are the painful areas. 

(2) Disturbance of Vision. — This is in direct proportion to the 
amount of cloudiness which has occurred in the media. Very 
great impairment of visual acuity denotes extension of the disease 
to the ciliary body or deeper structures. 

During iritis, transient myopia and astigmatism are commonly 
present. Especially in the plastic types of the disease, even 
after full pupillary dilatation, an increase in the refractive power 
is demonstrable. Although there are changes in the corneal 
curvature, according to Oliver the bulk of the ametropic change 
in such cases is due to perversion of the lens-action from spastic 
accommodation (Roller) as the result of ciliary irritation. 

(3) Tenderness of the Globe. — This occurs even in uncom- 
plicated iritis, especially of rheumatic origin, but if severe, sug- 
gests inflammation of the ciliary body. 

(4) Photophobia and Lachrymation. — These symptoms vary 
considerably in degree, being almost or quite absent in some 
varieties, and severe in those of acute and violent onset. 

(5) Malaise, fever, nausea, and marked depression, occasionally 
are experienced by the patient, the last often being the result of 
prolonged pain and insomnia. 

Diagnosis. — The salient symptoms of iritis just detailed are 
sufficient for the purpose of diagnosis ; nevertheless, it is not 
uncommon to find a case of iritis mistaken for some other ex- 
ternal inflammation, and valuable time is lost by the useless ap- 
plication of astringent remedies. Most commonly, cases of simple 
iritis have been mistaken for one or the other types of conjuncti- 
vitis, and the following table may be found useful : — 



314 



DISEASES OF THE EYE. 



Iritis. 

1. Severe brow pain, 
worse at night. 

2. Dim vision. 



3. Fine pericorneal in- 
jection. 

4. Absence of secre- 
tion ; some abnormal 
lachrymation. 

5. Sluggish or immo- 
bile pupil. 

6. Iris discolored. 

7. Abnormal reaction 
to mydriatic. 

8. Severe photophobia 
exceptional. 

9. Conjunctiva usu- 
ally translucent ; occa- 
sionally chemotic. 

10. Slight tenderness 
on pressure. 

11. Posterior syne- 
chia. 



Simple Conjunctivitis. 

Feeling of foreign body 
in the eye. 

Vision usually unim- 
paired, unless secretion 
is very abundant. 

Coarse conjunctival in- 
jection. 

Muco-purulent dis- 
charge ; flakes of lymph. 

Pupil unaffected. 

Iris unaffected in color. 

Normal reaction to my- 
driatic. 

Severe photophobia ab- 
sent in simple cases. 

Conjunctiva opaque, 
velvety, and at times 
chemotic. 

Tenderness not mark- 
ed. 

No synechiae. 



Phlyctenular Conjunc- 
tivitis. 

Acute general irrita- 
tion. 

Vision impaired by 
corneal involvement. 

Diffuse injection, with 
special lines of vessels 
running to phlyctenules. 

Free lachrymation. 



Pupil usually unaf- 
fected. 

Iris unaffected in color. 

Normal reaction to my- 
driatic. 

Severe photophobia 
and blepharospasm. 

Conjunctiva translu- 
cent, bathed in tears. 



Tenderness not mark- 



ed. 



No synechise. 



Many variations in the types of iritis make it impossible to 
formulate unvarying rules for the establishment of a differential 
diagnosis, but attention to these points may prevent mistakes. 

A diffuse scleritis somewhat resembles in its color the zone of 
pericorneal injection more or less characteristic of iritis, which. 
indeed, may be a complicating symptom of this disease. Acute 
glaucoma bears some resemblance to acute iritis (for the distin- 
guishing points see page 379). 

Course, Complications, and Prognosis. — An iritis may 
pursue an acute course, reaching its termination in four to eight 
weeks, or be chronic from its onset and last in a slow and in- 
sidious inflammation, for long periods of time. The termination 
of an iritis may be entirely favorable. The inflammatory adhe- 
sions disappear, and the iris regains complete mobility, only a few 
traces of iris pigment being seen on the capsule of the lens. 
On the other hand, more or less complete attachment causing 



PINK VNKN OF TIIK IRIS. 



315 



Fig. 103. 



distortion and inequality of the pupil (consult Fig. 102) mav 
remain ; or deposits of exudate may directly occlude the pupil 
and lie upon the capsule of the lens. 

The binding down of the iris 
throughout the whole extent of its 
pupillary edge, although the pupil 
itself remains clear, is denominated 
exclusion of flu pupil; if the pupil is 
filled in with opaque inflammatory de- 
posit, the term occlusion of the pupil is 
applied. With extensive or annular 
synechia? the angle of the anterior 
chamber becomes obliterated, the iris is 
bulged forward except around its pupil- 
lary margin, which is bound down, so 
that a crater-like depression is evident, 
and the appearance denominated "iris 
bombe" is developed. (Fig. 103.) This 
leads to increased tension, secondary 
glaucoma, and even detachment of 

the retina, unless the communication Exclusion and occlusion of 
between the anterior and posterior the pupil. The iris is adherent 

ii /> ,i . ] i by its entire pupillary margin 

chambers of the eve is restored bv ; 4 , , 7™. 

' to the lens. The posterior 

Operative measures. chamber {h) is thus made 

The following tissues of the eyes deeper, the anterior chamber 

i . ill- ,i M shallower, especially where 

mav become involved during the ., . „., . . , ,. , 

£> the root of the iris (a) is pressed 

COlirse of an iritis : The cornea (kera- against the cornea. The retinal 

titis punctata); the ciliary body (irido- pigment is beginning to sepa- 

.... x ,. , .,,."., *, . ,. rate at s. The pupil is closed 

oydtiis); the choroid (vndo-ehoroidir- by au exudate membraiK . . 
tis); the vitreous (hyalitis); and the in the lower part of the ante- 
optic nerve and retina (hypercemia, or rlor chamber there is matter 
.. ... * ir . 2 , ,, r . (») precipitated upon the pos- 
neuro-retimti*). A\ ith these facts in terior surface of the cornea 

mind, and with the tendency of certain The cortex of the lens has be- 
fcypes of the disease to relapse, a prog- corae cataractous to; «*« 11U " 

. lii- cleus (]fe) is unaltered. (Fuchs.) 

nosis must be guarded, but in un- 
complicated iritis, seen early and properly treated, a perfect result 
may be obtained in the large majority of cases. 




316 DISEASES OF THE EYE. 

Treatment. — This depends upon several indications: (1) The 
suppression of pain by warm fomentations or dry heat, local blood- 
letting, and the internal administration of analgesics. (2) The 
maintenance of mydriasis by atropine. (3) The recognition of 
the cause and the exhibition of suitable internal medication, as 
well as the administration of remedies having the general physio- 
logical action of alteratives, even if the exact cause cannot be 
ascertained. (4) The use of surgical interference according to 
the indications. The description of the treatment in detail is 
reserved for the subsequent sections devoted to the particular 
consideration of the various types of iritis which follow. 

Iritis is divided, according to its character and course, into 
acute and chronic iritis; according to its pathological nature, 
into plastic, parenchymatous and serous iritis ; and according to its 
supposed etiology into syphilitic, rheumatic, gouty, gonorrhceal } 
diabetic, tubercular, scrofulous, cachectic, idiopathic, traumatic, 
sympathetic, and secondary iritis. 

Simple Plastic Iritis runs an acute, subacute or chronic course, 
and is the most common form of the disease. The salient symp- 
toms of iritis are present : discoloration of the iris, pericorneal 
injection, immobility of the pupil, and the formation of posterior 
synechia?. 

Not only may the ordinary attachments form between the iris 
and the capsule of the lens, but a plastic exudate may cover 
the pupil-space with a false membrane, and in some cases a gela- 
tin-like mass is deposited in the anterior chamber. When this 
material consolidates, its appearance has been compared by 
Schmidt-Rimpler to that of a dislocated lens in the same posi- 
tion ( fibrinous or spongy iritis). Plastic iritis is seen in — 

1. Syphilis. Syphilitic Plastic Iritis. — "When plastic iritis 
appears in the early stages of general syphilis, or in the stages 
of the mild exanthematous manifestations (the condylomata and 
the inflammations of the mucous membranes), it is not accom- 
panied by characteristic clinical symptoms, which of themselves 
justify the diagnosis of syphilis. 

The percentage of cases of syphilis which acquire iritis during 
the course of the disease, varies from 0.42 to 5.37 according to 



DISE kSES OF THE EBIS. 317 

different authorities; bat among cases of iritis, syphilis has been 
found tn be the cause in from 30 to *>0 per cent. (Alexander.) 

This form of iritis is common between the second and ninth 
month after the initial lesion, but may be delayed until the 
eighteenth month. Some authors have placed the appearance of 
plastic iritis in the gummatous stage of syphilis, but it is more 
probable that in such cases a few Bynechise, remaining from a 
plastic iritis in the early stages, have caused a relapse in this late 
period. 

Commonly both eyes are attacked, one a little later than its 
fellow ; occasionally the onset is simultaneous. The course 
usually is acute and after thorough cure, relapses are not common. 
A subacute or chronic type is also described. 

Acute iritis of the plastic type is rare in new-born infante 
of syphilitic heritage; but has been described in children with 
inherited syphilis, from the second to the fifteenth month. Acute 
iritis in children in the first months of life, and also in the later 
childhood pears, usually is the result of hereditary syphilis ; a 
late manifestation may assume the serous type of the disease. 
In addition to the symptoms of severe plastic iritis, secondary 
inv( tlvement of the vitreous and ciliary body is liable to take place. 1 

In scrofulous and anaemic children, a form of iritis called 
scrofulous iritis has been described, which resembles the disease 
produced by inherited syphilis. 

Treatment. — The most important local drug in this as in 
other forms of iritis is atropine (gr. iv-fsj), several drops to be 
in-tilled in the conjunctival cul-de-sac every three or four hours. 
Mydriasis should be maintained until all ciliary irritation has 
subsided and during the period of changes in the refractive power 
of th - e page 313). 

Pain is relieved and at the same time congestion is diminished, 
thus rendering the mydriatic action of the atropine more certain, 
by leeching the temple — one to three Swedish leeches being 
applied near the line of the hair, or blood is drawn by an arti- 
ficial leech. In the absence of a regular Heurteloup this may t>e 

1 Some authorities hold that in syphilitic iritis, change in the parenchyma 
of the iris with the formation of small nodes, in some instances undistinguish- 
able by ordinary methods, is always present. 



318 DISEASES OF THE EYE. 

accomplished by making an incision in the temple with a scalpel 
and using a small cupping-glass, to which a piston is attached for 
exhausting the air. Instead of using atropine in solution, some 
surgeons prefer to employ it incorporated with vaseline, or even 
to place a small quantity of the solid drug directly in contact 
with the cornea. Should atropine not be tolerated, hyoscyamine, 
hyoscine, scopolamine, or duboisine may be substituted. Their 
mydriatic effect is increased by the addition of cocaine. 

The constant use of atropine leads to disagreeable dryness of 
the throat. This may be obviated in part by compressing the 
tear-duct after each application. It may be relieved by giving 
the patient a gargle made of equal parts ice water and a strong 
decoction of coffee. Small doses of morphia are said to be of 
service, and pilocarpine and pellitory lozenges are useful. 

Pain is further relieved by the application of moist or dry 
heat ; the latter is best done by means of cotton batting which 
is held before a fire and then laid upon the affected eye, to be 
replaced by a freshly heated mass as soon as cooling occurs. 

The best constitutional treatment is some form of mercury : 
either the protiodide, blue mass or calomel given, as in syphilis 
generally, just short of the point of salivation, and continued for 
many weeks eveu after all acute symptoms have subsided. 
When it is important to obtain rapid mercurial action, inunctions 
are advantageously employed. Hypodermic injections of mercury, 
particularly mercuric chloride, are strongly advocated by some 
surgeons. During the time that mercury is being pushed to the 
point of tolerance, the gums must be carefully watched for signs 
of sponginess, and the patient should frequently use a chlorate- 
of-potassium mouth-wash. 

After the course of mercury, iodide of potassium is indicated, 
for its own effect and for eliminating the mercury ; later this may 
be combined with the bichloride of mercury. 

In old syphilitics, with much cachexia, in whom a plastic iritis 
improperly treated in the early period lias relapsed, it is not 
always wise or possible to induce active mercurialization. For 
them bichloride combined with the tincture of iron is a suitable 
remedy. Subconjunctival injections of bichloride of mercury 
(2 to 4 drops of a 1-1000 solution), if there is not too much 



DISEASES OF THE IRIS. 319 

circulatory stasis, as advocated by Darier and others, arc .sonic- 
times singularly efficient, as the author can testily from experi- 
ence. Similar injections of salt-solution are equally valuable. 

2. Rheumatism. Rheumatic Iritis. — This disease occasions 
iritis of a plastic form, or rather, rheumatism is a predisposing 
cause of many cases of iritis, in the opinion of some authors, 
(Berry) the rheumatic form being the most common of all the 
types. 

It occurs between the ages of twenty and fifty, either with or 
without coincident rheumatic affections, and varies considerably 
in the aggressiveness of its symptoms. Not uncommonly these 
are severe, with much pericorneal injection, acute pain, greater 
usually than in syphilitic cases, and tenderness of the globe. 
Most frequently one eye is affected ; the inflammation rarely is 
simultaneously symmetrical. The second iris becomes inflamed 
after a longer or shorter interval. 

Relapses are frequent, in this particular differing from syphilitic 
plastic iritis, and a patient once having had an attack of rheu- 
matic iritis is liable at intervals of months or even years, again 
to be attacked. If treatment is begun early, even in recurring 
attacks, perfect cure may be expected, as extensive exudation of 
lymph is uncommon. 

The frequent relapses of rheumatic cases have given rise to the 
term recurrent iritis, applicable to some varieties. 

A form of plastic iritis exists, aptly called "quiet iritis" 
(Hutchinson), in which there is no pain nor ciliary congestion, 
the only symptom being the progressive dimness of vision 
which leads to its discovery, and which is caused by rheuma- 
tism or inherited arthritic tendency in a majority of cases, but 
which may also depend upon syphilis. 

Treatment. — The use of atropine in the manner already de- 
scribed is of paramount importance. Leeches and moist and dry 
heat will help to relieve the pain. Frequently these measures 
will not be sufficient, and morphia or codeia may be administered. 
Much comfort often results from the administration at night of 
Y^y of a grain of hyoscine. Rubbing the brow with an oint- 
ment of mercury and belladonna is of some service. 

Anti-rheumatic remedies are of great importance, and much 



320 DISEASES OF THE EYE. 

reliance may be placed upon salicylic acid, salicylate of sodium, oil 
of gaultheria and the alkalies, the last, in the form of the mistura 
potassii citratis, being advantageously combined with tincture of 
aconite if restlessness and fever are associated symptoms. 

The tendency of rheumatic iritis to recur, requires preventive 
treatment in the form of regulated diet, the use of mineral waters, 
and proper attention to change of clothing according to the vicissi- 
tudes of the climate. 

In rheumatic iritis, which has assumed a chronic type, or if 
there has been exudation of lymph, or involvement of the ciliary 
body, mercury may be exhibited to obtain its alterative eifect ; 
for the same reason iodide of potassium is required. 

3. Gout. Gouty Iritis. — This resembles rheumatic iritis in its 
tendency to relapse and to attack one eye at a time. An iritis 
may reveal a gouty diathesis previously latent and unsuspected, 
and may appear as the first symptom of this affection, to be 
followed by an outbreak of gout elsewhere in the body. 

A form of iritis, insidious in character and destructive in 
tendency, almost invariably associated with disease of the vitreous, 
occasionally occurs in children of gouty parents. These children, 
according to Mr. Hutchinson, have a peculiar squareness of 
build, heavy features, florid complexions, and feebleness of circu- 
lation in the extremities. 

Treatment. — The usual measures to relieve pain and main- 
tain mydriasis are indicated, together with appropriate anti-gout 
diet, citrate of lithium, salicylate of lithium, colchicum, iodide 
of potassium and hypodermics of pilocarpine. Change of climate 
may be necessary. In the chronic cases, tonics are suitable 
remedies. 

4. Gonorrhoea. Gonorrhceal Iritis. — This is a rare form of 
iritis, chiefly plastic in character, which usually does not coincide 
with nor follow the gonorrhceal attack ; an arthritis of the knee, 
or sometimes of the ankle, intervenes. It has been explained by 
the influence of the gonococci on the iris. Like the rheumatic 
types, it is attended with severe pain, in addition to the usual 
symptoms of iritis. It may relapse with each new attack of 
gonorrhoea. 



DISEASES OF THE [RIS. 



321 



Treatment. — The local use of atropine, etc. If the urethra 
is inflamed, this musl receive attention ; but, as ju-i stated, usually 
the gonorrhoea and the iritis do not coincide. Iodide of potas- 
sium may be tried, and mercury, if there is much exudate. 
Relief will follow profuse sweats by means of pilocarpine given 
hypodermically or in the form of the fluid extract of jaborandi. 
Subconjunctival injections of mercury are sometimes efficient. 

5. Diabetes. Diabetic Iritis. — The subjects of diabetes may 
develop a plastic iritis, not only after an operation involving muti- 
lation of the iris, but independently of any exciting cause. The 
disease is intractable and sometimes is complicated with hemor- 
rhage into the anterior chamber. On account of the occasional 
association of diabetes and iritis, an examination of the urine 
i- advisable in all cases of stubborn iritis. 

TREATMENT. — This requires the usual local remedies for iritis, 
and the treatment suited to diabetes. 

Parenchymatous Iritis is characterized by general or localized 
discoloration or -welling of the iris, owing to inflammation and 
cellular proliferation within its tissues. 

The swelling may be general and the margin of the pupil tied 
down to the capsule of the lens by exudation; or small yellowish 
nodosities, crossed by vessels near their free borders, rise percepti- 
bly above the level of the iris, and gradually shade away into its 
structure. The effusion into the 
parenchyma of the iris may be- 
come purulent, with filling up 
of the pupillary space and the 
formation of hypopyon. Pa- 
renchymatous iritis is seen in — 

1. Syphilis — Syphilitic 1'"- 
renchymatcms Iritis; Iritis Pa- 
pulosa; Gummatous Litis. — In 
the later secondary stage of 
syphilis a form of iritis occurs, 
differing from the plastic variety 
by the development of clinical features, characteristic of the dis- 
order which has produced it. 

21 



Fig. 104. 




Gummatous iritis. 



322 DISEASES OF THE EYE. 

This is indicated by the appearance in the inflamed iris, if it 
occurs during the course of a plastic iritis, or independently <>t 
this antecedent condition, of one or more yellowish, reddish- 
yellow, or reddish-brown nodules, varying in size from a hemp 
seed to a small pea, situated at the pupillary or ciliary border, or 
occasionally between the two, in the iris tissue. They are crossed 
by fine vessels. They vary in number from one to four, the in- 
tervening iris tissue being comparatively unaffected, and belong, 
in spite of their resemblance to gummata, to a comparatively 
early period of syphilis. They are gradually absorbed without 
leaving distinct scars or atrophy of the iris tissue, to mark their 
former situation. 

This is the so-called gummatous iritis, although some writers 
(Alexander) reserve this name for the formation of true gumma 
of the iris, and describe the present type as iritis papulosa. 

Gumma of the iris, according to Alexander, appears almost con- 
stantly at the ciliary border, is solitary, of the size of a pea or 
small nut, grows toward the ciliary body, and disappears through 
fatty degeneration, leaving behind a permanent scar or atrophy of 
the iris. This appears in the so-called tertiary period of syphilis, 
or that period in which gummata in other organs are found. 

The disease known under the name "gummatous iritis," or 
sometimes " true syphilitic iritis," is not common ; Alexander, 
however, states that in more than 27 per cent, of iritis he has 
found that form of iris-change which is described by the general 
term " iritis gummosa." 

Treatment. — The same treatment described in connection 
with syphilitic plastic iritis is applicable, and mercury should 
be pushed until complete absorption of the nodes has been 
obtained. 

In true gumma of the iris, on the other hand, the free use of 
mercury is not always permissible owing to the cachectic state of 
the patient, and because more rapid absorption appears to take 
place under ascending doses of iodide of potassium, which may be 
given in a decoction of sarsaparilla. 

Infectious Disease Iritis is seen in association with recurrent 
fever, pneumonia, typhus and typhoid fever, and a. purulent iritis, 
as the result of embolism, occurs in the course of sept icsemia after 
puerperal fever, and in pyaemia. 



DISEASES OF THE IKI-. 323 

In malaria a periodic iritis with hypopyon has been described, 
and somewhat analogous to this is another periodic iritis, or irido- 
cyclitis, which has been seen before each menstrual period (iritis 
catamenalis), perhaps due to abnormalities in the uterine dis- 
charge. 

The management of such cases depends upon general princi- 
ples, the free use of quinine and stimulant.- being appropriate 
in purulent iritis. 

Idiopathic Iritis, or one in which no local injury or constitu- 
tional disease can be accredited with its origin, is rare in elderly 
people, occurs in adults, chiefly men, and has been described in 
children especially, in a slight plastic form, in girls nearing 
puberty. 

Idiopathic iritis has been ascribed to cold, but often no cause 
can be given ; it usually is monolateral. 

Traumatic Iritis occurs as the result of an injury, either acci- 
dentally inflicted or made in the course of an operation ; e. g., 
cataract extraction. 1 In this category are placed, also, those cases 
of iritis which follow discission of the lens and the production 
of iritic inflammation by contact of the iris with the swelling 
cortical material. Most frequently the cause, when not brought 
about in the manner just stated, is infection carried directly into 
the wound. 

Treatment. — The usual local measures are advisable, and 
if the inflammation is seen in the first stage of its development, 
iced compresses are suitable, for the same reason that they are ap- 
plicable in wounds of the eyeball generally. These must not be 
used late in the disorder, nor in any other form of iritis. 

Sympathetic Iritis (see page 337). 

Secondary Iritis, or that form which appears with other dis- 
eases of the eye by the spread of the inflammation, is most com- 
monly seen in association with diseases of the cornea which present 
themselves in the form of sloughing or perforating ulcers, and 
has been described in this connection. Scleritis of the deep 
variety is often associated with iritis. 

More rarely the primary disease begins deep in the eye ; e. g., 

1 Spongy iritis page 316) is occasionally seen after cataract extractions (Knapp). 
Strong eolations of eserine may produce plastic iritis {Eserine iritis). 



324 DISEASES OF THE EYE. 

by detachment of the retina. The pressure of intraocular tumors 
or vitreous exudates may occasion a secondary iritis. 

The treatment consists in proper applications to the original dis- 
ease, with such measures as are suitable under the circumstances 
to relieve the iritis. The presence of iritis in corneal ulceration is 
one of the contraindications for eserine. 

Serous Iritis (Descemetitis, Aquo- Capsulitis, Keratitis Punc- 
tata, 8erous Oyclitis). — This affection has been described in part 
on page 290, and is characterized by a serous or more commonly 
a sero-plastic exudate, deepening of the anterior chamber, slight 
dilatation of the pupil (at least an uncontracted pupil), haziness of 
the cornea and aqueous humor, and a precipitate of opaque dots, 
upon the posterior elastic lamina of the cornea, generally arranged 
in a triangular manner, with the apex pointing upward. There 
is a slight pericorneal injection, no great tendency to form 
synechia, and the tension is apt to be higher than normal, at 
first, but later diminishes. Posterior synechias form later, and if 
they are extensive, secondary glaucoma. 

In serous iritis, Collins has found pathological changes in the 
glands of the ciliary body, and hence the recommendation of 
Priestley Smith, that this disease be designated serous cyclitis, is 
appropriate. 

Serous iritis is seen in association with disease of other portions 
of the eye, and appears as one of the manifestations of sympa- 
thetic ophthalmitis (page 337). It may arise, like the other 
forms of iritis, from a true syphilitic basis in the early stages of 
this disease (Alexander), or as a late manifestation, the average 
time being thirteen years after infection (Brailey). It is more 
common in women than in men. It is often observed with men- 
strual and pelvic disorders in anaemic patients, and also with 
rheumatism and gout. 

Treatment. — The rule, previously given, to maintain com- 
plete mydriasis with atropine, meets with an exception in this 
type of iritis. The drug must be applied with great caution, a 
continual watch being kept on the tension. Diuretics, laxatives 
and diaphoretics are indicated. Iodide of potassium acts well, 
and turpentine in full doses has found favor with some surgeon-. 
Should a syphilitic origin be determined upon, the usual remedies 



DISEASES OF THE [BIS. 



325 



are applicable. Any rise of intraocular tension, unless extremely 
temporary, should 1"- overcome by paracentesis corneae. In the 
event of persisting increase of intraocular ten-ion an iridectomy 
may be required. 

Chronic Iritis. — Any type of iritis may assume au acute, sub- 
acute, or chronic course ; it' the last, no additional symptoms 
occur, 1 nit those ordinarily present arc modified by the chronieity 
of the stages. 

Iu addition to the chronic type of an ordinary iritis there re- 
mains to be described one which has received the name plastic 
irido-choroiditi8 } because of the complications of disease of the 
choroid and vitreous, leading to the formation of a secondary 
cataract. This disease occurs in adults, usually without assign- 
able cause, is symmetrical and proceeds steadily in a tendency 
destructive to the nutrition of the eye. (See also page 334.) 

The treatment of the latter condition is unsatisfactory, alter- 
ative-, tonic- and operative measures often meetiug with indiffer- 
eut success. 

Operative Treatment in Iritis. — In ordinary acute iritis 
the tension does not rise. In serous iritis, continued elevation of 
ten-ion indicates paracentesis. 

Pure types of iritis are practically never complicated with the 
formation of hypopyon, although this is not uncommon with 
ndary iritis, and in irido-cyclitis. A cheesy or purulent 
detritus may partly fill the anterior chamber in gummatous iritis. 
In such cases the evacuation of the content- by Saemisch's opera- 
tion would be appropriate. 

An iridectomy may be needed in recurrent iritis, or in an iritis 
which refuses to heal completely, some ciliary injection and irri- 
tability remaining. It is a nice point to decide upon the appro- 
priate cases for operation. Those cases which present the least 
change in the iris, in which the aqueous humor is clear and the 
tension is not subnormal, are most likely to yield a good result. 
Iridectomy in recurrent iritis of rheumatic type does not insure 
the patient against further attacks. 

In chronic iritis, circular posterior synechia? and bulging of 
the- iris are the most important indications for the operation. 
Determined rise of tension and threatening glaucoma, under any 



326 DISEASES OF THE EYE. 

circumstances, furnish reasons for its performance. According 
to Nettleship, keratitis punctata, chronic thickening of the iris 
with very extensive attachments, the existence of myopia, a 
tendency to spontaneous bleeding, and hypopyon render the 
operation less desirable; if the tension is below the normal, the 
operation may be followed by bleeding and shrinking of the eye- 
ball. 

An iridectomy is performed to secure one or all of three ends : 
(a) Prevention of recurring attacks ; (6) re-establishment of the 
communication between the anterior and posterior chambers of 
the eye, with consequent improvement in its nutrition and aversion 
of threatened glaucoma ; (c) improvement in vision by the sub- 
stitution of an artificial pupil for one that has been occluded or 
excluded. 

The point for the operation must be determined in large measure 
by the condition of the iris, that portion being selected for excision 
which is least changed and least bound down by adhesions. 

Before operating, great care should be exercised to note the 
tension, the state of the iris, and, if possible, of the deeper 
structures, and to obtain a map of the field of vision. If these 
examinations indicate much deep disease, strong reasons are pre- 
sent for declining to operate. 

Posterior synechise remaining after the acute symptoms of 
iritis have subsided, have been regarded as a cause of relapse 
or recurrence, and, although this has not been proven, several 
operations have been devised for severing such attachments, to 
which the general term corelysis has been applied. 

Tumors of the Iris — Cysts. — Cysts, having transparent, deli- 
cate walls lined with pavement epithelium (serous cysts), may 
develop in the iris as the result of an injury, and may be situated 
in the substance of the iris, or have a superficial position. Im- 
plantation of a cilium in the anterior chamber may be the start- 
ing point of an epithelial pearl-like tumor (pearl-cyst or chole- 
steatoma), essentially cystic, with a lining of laminated epithelium 
and semi-solid contents of degenerated epithelial cells and fat 
globules (F. R. Cross and E. T. Collins). 

A cyst may be minute, or grow and fill the anterior chamber; 
both eyes may be affected, and some instances of multiple iris- 



IMSKASKs <>F TIIK IRIS. 



327 



Fig. 105. 



cysts are on record. A cyst may cause irido-choroiditis and sym- 
pathetic ophthalmitis by pressure. An attempt should be made 
to remove it through an incision, the growth and surrounding 
iris being seized, drawn out and exeised. 

Tubercle of the Iris (Tubercular iritis). — In a certain number 
of eases small grayish-red nodules develop at the margin of 
the pupil, bearing great similarity in their external appearance 
to miliary growths. Such growths may disappear, posterior 
synechia' remaining at their points of origin, or successive de- 
velopments of new nodules lead to a plastic inflammation of the 
iris and ciliary body, and shrinking of the eyeball. Under these 
circumstances tubercle of the iris appears in the form of an iritis. 1 

Tubercle of the iris also occurs in a solitary form, a yellowish 
nodule growing from the periphery of the iris, covered, it may be, 
with smaller bodies. 

The average age of persons affected 
with primary tuberculosis of the iris is 
twelve years ; one or both eyes may be 
affected, more commonly the former. Al- 
though the patients may present no other 
signs of tuberculosis, this, and in a fatal 
form, may become a sequence. Bacilli 
and giant cells are found in these growths, 
proving their true nature. If operation 
is undertaken, it should be the removal 
of the entire globe ; iridectomy has been 
almost uniformly unsuccessful. 

Sarcoma of the Iris (Melano-sareoma) 
is rare as a primary disease. It is usually 
pigmented. At first of slow growth, later 
it increases rapidly with pain, hemorrhage, 
etc., and finally bursts forward through 
rupture of the globe. It is most com- 
mon in females, and usually occurs between 20 and 40, the lower 
part of the iris being generally affected. (Fig. 105.) 

1 In the opinion of certain authors these small tumors should not be re- 
garded as tubercles of the iris, and have received the name granulomata, a 
tnrrn also applied to prolapses of the iris which are covered with granulation 
tissue. 




Sarcoma of the iris 
(Andrews). 



328 DISEASES OF THE EYE. 

It is noteworthy that in a number of instances sarcoma of the 
iris has supervened upon simple melanoma of the iris. This 
latter is a dark tumor, developed from the pigment stroma of 
the iris, and, commonly passive and innocuous, is occasionally in 
another form, as just stated, the percursor of sarcoma. 

An exceedingly rare tumor is the non-pigmented iris-sarcoma 
(leuco-sarcoma). This may be complicated with serous iritis. 

In the early stages, when the growth is circumscribed, favor- 
able results follow excision of the diseased portion of the iris ; 
later enucleation of the globe is necessary. 

Very rare forms of iris tumor are vascular growths (naevi) ; 
leprosy nodules, and lymphomata. 

Injuries to the Iris. — Wounds. — An incised wound limited to 
the iris does not necessarily produce serious results. It will be 
followed by blood in the anterior chamber, which in course of 
time is absorbed. Wounds, however, are rarely limited to the 
iris, but having penetrated the ball through the cornea or ciliary 
region, lead to the danger of sympathetic irritation, or injure the 
lens, and produce traumatic cataract. 

In the first instance atropine, to secure physiological rest of 
the iris, and a compressing bandage, will lead to a speedy cure ; 
in the other instances the extent and position of the wound will 
determine the necessity for enucleation, or for the treatment 
applicable to traumatic iritis. 

Foreign Bodies. — A foreign body may penetrate the cornea and 
lodge upon the iris, or having partially penetrated the cornea, 
may be pushed through it in the efforts at dislodgmcnt, and 
become entangled in the iris. In either event it should be 
removed. 

An opening is made with a broad needle, or narrow keratome, 
at the corneo-scleral junction, eserine having been previously in- 
stilled, and a pair of forceps passed into the wound with which 
the body is seized. If this is not possible, the piece of iris upon 
which the substance lies should be drawn through the wound and 
excised. 

Certain injuries to the iris are produced by the effects of blows 
upon the eye, and are described under the following names : — 




DISEASES OF IITE IRIS. 329 

Trido-dialysis, or a rupture of the ciliary attachment of the iris 
(ligamentum pectinatum). By this means an opening is pro- 
duced, comparable to a false pupil ; it may be detected by the red 
reflex which shines through the 
artificial aperture, usually some- Fm - 106. 

what semi-lunar-shaped] situated 
in the periphery of the iris at the 
corneo-scleral margin. (Fig. 106.) 
This may be quite small or in- 
volve more than half the circum- 
ference. 

In a few instances, re-attach- irido-dialysis. 

ment of the ruptured fibres has 

taken place under the favoring influence of atropine, which should 
be vigorously instilled. Ordinarily the lesion is permanent, and, 
if small, occasions little trouble, although there may be diplopia. 
Pain, some dread of light and hemorrhage into the anterior 
chamber, are the immediate sequences of such an accident. 

Rupture of the sphincter produces mydriasis, and according to 
some authorities the not uncommon dilatation of the pupil [trau- 
matic mydriasis), which follows a blow, is always accompanied 
by such a lesion. The condition is not altered by treatment. 

Displacement of the iris occurs under three forms: (1) Retro- 
flexion, or a folding back of a portion of the iris upon the ciliary 
processes, usually accompanied by a partial dislocation of the 
lens ; (2) anteversion, or turning upon itself of the detached 
portion of the iris, so that the under or uveal surface is exposed ; 
and (3) aniridia, or complete detachment of the iris from its in- 
sertion, so that it lies in the anterior chamber, or even under the 
conjunctiva. An injury severe enough to produce this condition, 
will usually be attended by other serious lesions of the remaining 
structures of the eye. 

Anomalies of the Anterior Chamber. 

(a) Alterations in its Depth. — These are seen under a variety of 
conditions. Physiologically the anterior chamber is shallower in 



330 DISEASES OF THE EYE. 

infancy and old age, and diminishes in its middle depth during 
the act of accommodation. 

Pathological deepening of the anterior chamber occurs in luxa- 
tion or absence of the lens, in serous iritis and some cases of 
eyclitis, and is present in conical cornea and certain forms of 
staphyloma. 

Pathological shallowing of the anterior chamber occurs in 
chronic iritis with bulging forward of the iris, in glaucoma, and 
in the later stages of growths of the interior of the eye. Its 
depth is also lessened when there is diminution of the secretion 
of aqueous humor, in old cases of inflammation of the uveal 
tract with detachment of the retina. 

(b) Alterations in its Contents. — These may consist in mere 
turbidity of the aqueous as in iritis, keratitis punctata, and glau- 
coma, or there may be a positive collection of pus, several times 
referred to under the name of hypopyon, and commonly seen in 
sloughing ulcers of the cornea and purulent inflammations of the 
iris and ciliary body. 

Finally blood collects in the anterior chamber, a condition 
which receives the name hyphcema. This follows injury to the 
iris, accidentally or designedly induced, and occurs in tumors of 
the eye, hemorrhagic glaucoma, and in severe forms of iritis and 
eyclitis. It is also seen in haemophilia. Blood-staining of the 
cornea may cause a peculiar smoky hue, resembling a lens lux- 
ated into the anterior chamber. 

(c) Foreign Bodies and Parasites. — A foreign body penetrat- 
ing the cornea may lodge upon the iris or fall into the anterior 
chamber. This may be a sliver of iron or steel, or a particle of 
glass. Sometimes a cilium passing through a wound obtains 
entrance into the anterior chamber; if it remains long enough 
it causes a cystic tumor (implantation cyst). 

The two parasites described in this situation are cysticercus 
and jilaria sanguinis hominis. In all these instances the intruder 
should be removed by an operation. 



DISEASES OF THE CILIARY BODY. 331 



CHAPTER X. 

DISEASES OF THE CILIARY BODY, AND SYMPATHETIC 
IRRITATION AND INFLAMMATION. 

Cyclitis. — Under the general term eyelids are included various 
types of inflammation of the ciliary body. The close anato- 
mical connection of the iris, choroid, and ciliary body makes 
diseases limited strictly to the last structure, exceedingly un- 
common, just as in many instances inflammations primary in the 
iris or choroid, also involve the ciliary body. Hence when the 
iris and ciliary body are associated in pathological changes the 
term irido-eyelitis is applicable. 

Symptoms. — The symptoms which in general lead to the diag- 
nosis of cyclitis are the following : Injection of the circumcorneal 
or ciliary zone, neuralgic pain, and tenderness on pressure in 
this region ; change in the aqueous humor which grows turbid ; 
precipitates of exudation in grayish-brown points upon the 
posterior layer of the cornea, and at times hypopyon ; exudation 
in the posterior chamber attaching the under surface of the iris 
to the lens capsule in a complete posterior synechia, the retrac- 
tion thus produced causing a deepening of the anterior chamber; 
exudation into the vitreous causing opacities, especially in its 
anterior layers ; and alterations in the tension of the globe, which 
may be increased or decreased. 

The general symptoms of pain, photophobia, lachrymation, 
etc., are present in the acute types of the disease, and vision is 
seriously impaired according to the amount of the exudation in 
the pupillary space and vitreous. The following table, copied 
from Fuchs, may enable the student to differentiate between cases 
of pure iritis, and cases in which inflammation of the ciliary body 
predominates : — 



332 DISEASES OF THE EYE. 

Iritis. Irido-Cyclitis. 

1. Absence of unusual inflammatory ' 1. Severe inflammatory phenomena, 
phenomena. oedeina of upper lid. 

2. No decided tenderness on press- 2. Distinct tenderness on pressure, 
ure. 

3. No distinct changes in the ante- 3. Precipitates in the cornea ; re- 
rior chamber ; only slight turbidity of traction of the periphery or the iris 
aqueous. by total posterior synechia? and deep- 

I ening of the anterior chamber. 

4. Vision diminished in proportion , 4. Marked lessening of visual acuity 



to turbidity of aqueous. 

5. Unaltered intraocular tension. 



due to opacities in the vitreous. 

5. Tension altered — lowered 
raised. 



Varieties of Cyclitis. — Systematic writers divide cyelitis 
into three varieties : Simple or plastic, serous and purulent cyclitis. 

1. Simple, or Plastic Cyclitis, is characterized by severe ciliary 
pain and considerable pericorneal injection. The veins of the 
iris are dilated, its periphery is retracted by the action of the 
plastic exudate in the ciliary body, so that the pupil is dilated, 
or the anterior chamber is deepened. If the inflammation ex- 
tends, the hyperemia of the iris becomes an inflammation, the 
choroid is involved, and opacities form in the vitreous. 

2. Serous Cyclitis is characterized by slight pericorneal injec- 
tion and is unattended by severe pain. In the beginning, the 
pupil is dilated, the anterior chamber deepened, the aqueous 
somewhat turbid, and precipitates form upon the posterior 
layer of the cornea. (See Serous Iritis and Keratitis Punctata.) 

There is decided diminution of vision and the rapid formation 
of fine opacities in the vitreous chamber in its anterior portion. 
Very commonly the iris is involved (serous iritis), as well as the 
choroid. This leads to increased tension, narrowing of the pre- 
viously deepened anterior chamber, and the symptoms of glau- 
coma. 

3. Purulent Oyditis is characterized by intense ciliary pain, 
great pericorneal injection, and (edema of the conjunctiva and 
the upper lid. The vitreous becomes filled with large opacities, 
and a noteworthy feature is the formation of hypopyon, which 
may disappear and reappear again in a few days, its reappear- 
ance sometimes being signalled by a fresh exacerbation of intense 
jrain. The iris and choroid commonly are included in the inflani- 



DISEASES OF THE CILIARY BODY. 333 

ni:uion, the former both in a purulent and parenchymatous type, 
and the latter in a suppurative form. 

Course and Sequels. — Any form of cyclitis under vigorous 
treatment begun early, may terminate in healing and leave a 
useful eye. But the prognosis is always grave, because the dis- 
ease, especially in the serous form, is liable to originate glau- 
coma, and in the purulent form, or in the plastic variety which 
lias become purulent, tends to produce atrophy of the iris and 
choroid. The vitreous becomes filled with organic opacities, and 
by its contraction causes retinal detachment ; opacity of the lens 
and shrinking of the eyeball follow, or that condition known as 
phthisis bvlbi. 

Shrunken balls of this character are often tender, readily be- 
come inflamed, and may produce sympathetic inflammation in 
the fellow eye ; this is particularly true if the original inflam- 
mation has been a cyclitis of the plastic type, which in these in- 
stances probably remains in a chronic state. 

Causes. — As already stated, primary and uncomplicated dis- 
ease of the ciliary body is rare. The affection usually is part of 
a diseased process which involves the choroid or iris. 

Injuries are common causes of cyclitis, and the inflammation 
may follow operations upon the globe, e. </., cataract extraction. 
Syphilis attacks the ciliary body almost exclusively in the course 
of one of the forms of iritis, or in connection with disease of the 
choroid. In a few r instances gummata, strictly confined to the 
ciliary body, have been described. Cyclitis, the result of gout in 
a previous generation, has been recorded. 

Treatment. — The principles already enunciated in connec- 
tion with iritis, apply to the treatment of cyclitis, and need not 
be repeated. 

Injuries of the Ciliary Body. — The dangers attending perfo- 
rating wounds of the sclera have been described on page 305; 
this danger is doubly increased when the wound occurs in any 
portion of a zone, one-quarter of an inch wide, surrounding the 
cornea, a region commonly called the " dangerous zone," after 
Mr. Nettleship's apt description. All of the consequences of the 
primary infliction of the wound are present, in addition to the 
danger of plastic cyclitis and sympathetic inflammation. 



334 



DISEASES OF THE EYE. 



After a penetrating wound in this region two courses are open 
to the surgeon — an attempt to save the eve, or immediate enu- 
cleation. If an attempt be made on the side of conservatism, 
the plan discussed in scleral wounds (page 305) should be em- 
ployed ; if not, enucleation or a substitute for this is needed. 
The rules for this appear on page 340. 

Tumors of the Ciliary Body. — Round-celled sarcoma aud 
myxo-sarcoma have been described in this region. Sarcoma 
may not seriously impair the functions of the eye iu its earlier 
stages, but as soon as the nature of the growth — which first 
appears as a brown mass behind the iris, rarely in the angle of 
the anterior chamber — is known, the globe should be enucleated. 
Adenomatous and epithelial tumor formations may be demon- 
strated microscopically after bleaching (Collins). 

Gummata of the ciliary body have been referred to, and rarely 
are limited strictly to this region. Ossification of this structure 
has been recorded, and myoma also occurs. 

Fig. 107. 




Gummatous irido-cyclitis. 

Irido-choroiditis ( Oyclitis with Disease of the Vitreous and Kera- 
titis Punctata; Chronic Serous Irido-choroiditis). — Under tin- 
above names a disease of the eye is recognized, which, following 
Meyer's classification, is divided into two forms, according as the 
affection is primary in the iris or in the choroid. 

In the first instance there are mild iritis, insignificant pain and 
ciliary congestion, deepening of the anterior chamber, and spots 
in the posterior layer of the cornea as in serous iritis and kera- 
titis punctata. The chronic inflammation continues, relapses 
take place, exudation occurs behind the iris, while its pupillary 
margin is bound down so that the surface is irregularly or en- 
tirely bulged forward, and, if the pupil is not too much occluded, 



DISEASES OF THE CILIARY BODY. 335 

the ophthalmoscope will reveal flocculi in the vitreous. The ten- 
sion may now become raised and the eye pass into secondary 
glaucoma. 

In the other type the process passes from behind forward, 
beginning with patches of choroiditis, which increase in extent 
and depth, the nutrition of the vitreous is impaired and opacities 
form, the lens is altered and pushed forward, the iris becomes 
embodied in a plastic inflammation, with narrowing of the an- 
terior chamber and marked loss of vision. As the disease of the 
uveal tract continues the lens becomes opaque, the eyeball softens, 
the retina may be detached, and finally shrinking or phthisis 
occurs. 

This disease is chronic in course, and the symptoms, especially 
tin ise confined to the iris, are insidious. A cure may be obtained in 
the earlier stages, but the danger is the production of glaucoma 
through rise of tension, or atrophy and shrinking of the ball from 
extension of the morbid process. 

This affection usually occurs iu young adults, and commonly is 
symmetrical. It has been attributed to inherited gout, to rheu- 
matism and to syphilis. It also occurs from prolonged work asso- 
ciated with loss of sleep, from defective nutrition, and in women, 
apparently due to menstrual irregularities. In other instances 
no assignable cause is present, or the disease has started as the 
result of synechia? from a former iritis. 

Treatment. — In the earlier stages atropine, provided there 
is no rise of tension, should be employed ; in the event of increased 
tension without synechia?, cocaine and eserine may be used. 

Internally, mercury by inunction is indicated, if the patient is 
robust, but in the form of the bichloride combined with iron, if 
there is anaemia. Iodide of potassium may also be tried. 

When the presence of firm posterior synechia? has blocked 
the communication between the anterior and posterior chamber, 
this should be reopened by a good peripheral iridectomy, which, 
if the lens is opaque, may be combined with its extraction. Even 
in eyes in which softening has begun, provided the field of vision 
still remains intact, good results will sometimes follow a success- 
ful iridectomy. (Meyer.) 



336 DISEASES OF THE EYE. 

Sympathetic Irritation, and Sympathetic Inflamma- 
tion or Ophthalmitis. 

These terms are applied to affections in which one eye is impli- 
cated as the result of disease or injury to the other, and represent 
two essentially different conditions. 

It is customary to describe the eye which is implicated as the 
result of the disease or injury of its fellow as the sympathizing 
eye, and the one affected by the disease or injury which causes 
the implication the exciting eye. 

Conditions Producing Sympathetic Affections. — Ac- 
cording to Alt, 1 the entire nervous apparatus of the diseased eye 
participates in the transmission of the affection to the other. 
Generally one or other of the following conditions is present: — 

(a) Wounds of the ciliary region which set up a traumatic 
irido-cyclitis or uveitis. The ciliary region is the zone previously 
described by the term borrowed from Mr. Nettleship, " danger- 
ous zone." Traumatisms probably cause over 80 per cent, of 
the cases of sympathetic inflammation, (b) Foreign bodies in 
the eye. (c) Perforating wounds or ulcers of the cornea in which 
the iris has become incarcerated, or scars involving the ciliary body. 
(d) Operations upon the eye — extraction of cataract, sclerotomy, 
iridodesis, iridectomy, discission, and inclination, the last, of course, 
being a cause now practically eliminated, (e) Luxation, wounds 
and calcification of the lens. (/) Intraocular tumors when asso- 
ciated with irido-cyclitis (Schirmer). (g) Ossification and calcifica- 
tion of the choroid and ciliary body. (A) Pressure of an artificial 
eye or incarceration of the stump of the optic nerve in scar tissue, 
after the operation of enucleation. 

According to O. Schirmer, there is no sound evidence that herpes 
zoster ophthalmicus, symblepharon, intraocular cysticercus, sub- 
conjunctival rupture of the globe (without associated irido-cyclitis), 
or spontaneous inflammation of one eye can cause sympathetic 

1 It is stated that eyes which are, or have been, the subjects of purulent 
panophthalmitis do not produce sympathetic ophthalmitis. Alt, however, in 
his analysis of more than one hundred cases, found thirteen eyes enucleated 
for sympathetic irido-choroiditis, the other having been lost by purulent 
panophthalmitis. 



SYMPATHETIC INFLAMMATION. 337 

ophthalmitis, although sympathetic irritation may, 110 doubt, arise 
in consequence of any of these conditions. 

Sympathetic Irritation (Sympathetic neurosis) is a functional 
disturbance, which presents a series of symptoms, comprising 
photophobia, lachrymation, blepharospasm, defective or impaired 
accommodation, lessened visual acuity, inability to perform close 
\\<>rk, neuralgic pain through the distribution of the supraorbital 
nerve, photopsia, contraction of the field of vision and hyperemia 
of the eye-ground. 

With this there may be some tenderness or pressure over the 
ciliary region. Hence when observing an eye so affected that it 
is likely to produce either sympathetic irritation or sympathetic 
inflammation it is most important to watch for tenderness in the 
ciliary region, to measure the amplitude of accommodation, and 
to examine the field of vision. The tendency of this condition, 
which is looked upon as a neurosis, is to recur. It disappears 
entirely with the removal of the exciting eye. 

Symptoms in the Eye Exciting Sympathetic Irritation. — An eye so 
injured or diseased, that it is liable to produce the condition de- 
scribed in the preceding paragraphs, is apt to show, during the 
course of the irritation, attacks of congestion in the ciliary region, 
photophobia, tenderness on pressure, lachrymation and neuralgic 
pain. These may subside, just as the sympathetic irritation in 
the fellow eye may subside, and recur again and again. Sympa- 
thetic irritation may also be induced by minor lesions, for example, 
retained foreign bodies in the conjunctival cul-de-sac. 

Sympathetic Inflammation (Sympathetic ophthalmitis) occurs 
iu several forms, sometimes arising in the wake of an attack of 
irritation, sometimes coexisting with it, but frequently without 
any premonition or association of this character. None the less, 
if patients have had sympathetic irritation, it is proper to warn 
them that this may pass on to irremediable structural changes. 
On the authority of Mr. Gunn, it is stated by Nettleship that 
marked oscillation of the iris often occurs when a sympathetic 
irritation is about to give place to an inflammation. 

With or without warning, sympathetic ophthalmitis, or, as it 
should be called, sympathetic uveitis, presents itself: 

(1) As an irido-cyclitis, plastic or malignant, i. e., an infiam- 
22 



338 DISEASES OF THE EYE. 

raation characterized by pain, photophobia, pericorneal conges- 
tion, discoloration of the iris, closure of the pupil by exudation 
around its margin and behind the iris, tenderness over the ciliary 
region, narrowing of the anterior chamber, effusion into the vit- 
reous, opacity of the lens, detachment of the retina, and finally 
shrinking of the eyeball. 

(2) As a serous iritis, causing turbidity of the aqueous, deep- 
ening of the anterior chamber, punctate opacities on the posterior 
layer of the cornea, rise in tension, slight ciliary injection, and 
some opacity in the anterior layers of the vitreous. This may 
pass into a plastic iritis, or irido-cycUtis. Not infrequently, if not 
in all of the cases, there is a papillo-retinitis coexisting with the 
uveitis ; in some cases sympathetic papillo-retinitis is the primary 
affection. 

(3) As a choroido-retinitis in which the outlines of the papilla 
are hazy, the retina oedematous, the retinal veins dilated and 
tortuous, with or without the appearances of slight serous iritis. 
This is a rare manifestation. 

These symptoms in the sympathizing eye may be either acute 
or chronic. Often they come on insidiously and are not discov- 
ered by the patient until serious damage has been done. A pre- 
monitory symptom of great importance, and one which should 
always be searched for in cases in which sympathetic irritation 
or inflammation is likely to take place, is an almost character- 
istic tenderness in the ciliary region, frequently in a circum- 
scribed spot, which may be picked out with the end of a probe. 
When this is pressed upon, the patient shrinks from the touch 
in a peculiar and striking manner. Sometimes an exactly similar 
tender spot is found in the ciliary region of the exciting eye. 

Symptoms in the Eye Exciting Sympathetic Ophthalmitis. — Pre- 
ceding the development of any of the types of sympathetic oph- 
thalmitis, the exciting eye usually presents obvious iritis or irido- 
cyclitis, congestion, and alteration in the tension ; but the local 
manifestations in the exciting eye may not be characterized by 
pain, and consequently may escape attention, and although neces- 
sarily the vision is disturbed, the eye need not be a blind one. 
Indeed, there are no phenomena in the exciting eye which may 
be designated as characteristic. Schweigger is unwilling to recog- 
nize a clinical picture peculiar to the sympathizing eye. 



SYMPATHETIC INFLAMMATION. 

Tin Period of Incubation. — The period of incubation, or that 
period of time between the reception of the injury or disease in 
tin' exciting eye and the development of injkimmation in the 
sympathizing eye, varies considerably, in the majority of cases 
being from three to six weeks. Exceptionally, the disease begins 
a- early as the fourteenth day and has been postponed as late as 
twenty years, in Alt's collection one case being stated to have 
occurred as late as sixty years after the exciting disease. The 
maximum interval is, however, difficult to state with accuracy. 

Sympathetic irritation may arise within a very few days after 
the reception of an injury. It has occurred within the first 
forty-eight hours. 

Nature of Sympathetic Ophthalmitis. — Formerly it 
was almost universally thought that this disease was due to a 
reflex action through the ciliary nerves, and on this theory the 
name "sympathetic" was applied. The exact nature of this 
grave malady is not perfectly known, nor is the path of the 
morbid changes which precede the inflammation fully mapped 
out, although the older hypotheses have largely been abandoned 
for the theory of infection. 

According to Deutschmann, the inflammation is a progressive 
process in the continuity of the tissue of one eye to the other by 
way of the optic nerve-apparatus, and is of bacterial origin ; 
hence a migratory ophthalmitis. Deutschmann's researches have, 
however, not always been confirmed (Gifford, Mazza, Randolph, 
Limbourg, Levy and Greeff), and "the migration theory is still 
a hypothesis, just as is the ciliary nerve theory" (Greeff). The 
latter theory, in a modified form, i. e., that disturbances of nutri- 
tion and in the circulation, caused by irritation of the ciliary 
nerves in the "exciter," create the inflammation in the "sympa- 
thizer," is maintained by Schmidt-Rimpler. Even those who 
have failed to confirm Deutschmann's conclusions are unwilling 
to deny the parasitic origin of the disease, but believe that neither 
the micro-organism (perhaps its metabolic products) nor the route 
of transmission has been discovered. 

Treatment. — The most important consideration is prophy- 
laxis, or, in other words, the management of the eye originally 
affected. This depends upon the character and situation of the 



340 DISEASES OF THE EYE. 

wound, or upon the stage of the disease, and upon the amount of 
vision possessed by the injured or diseased organ. 

In the section devoted to treatment of wounds of the sclera, 
the method was pointed out by which eyes seriously wounded 
might be saved. 

It may sometimes happen, especially in private practice, when 
every advautage of nursing and careful watching is at hand, that 
eyes may be saved which would be sacrificed in the working 
classes. The attempt requires the gravest thought before it is 
undertaken, because the onset of a sympathetic ophthalmitis may 
be insidious, and when once beguu treatment rarely fully removes 
the structural changes which have taken place. The propriety of 
operating must be determined by regarding the following rules, 
which are modified from those given by Swanzy, and represent 
the published experiences of the best authorities. 

Enucleation, or one of its substitutes, should be performed on — 

1 . An eye with a wound so situated as to involve the ciliary 
region, and so extensive as to destroy sight immediately, or to 
make its ultimate destruction by inflammation of the iris and 
ciliary body reasonably certain. 

2. An eye with a wound in this region already complicated by 
severe inflammation of the iris or ciliary body, even if sight is 
not destroyed ; or an eye containing a foreign body which judi- 
cious efforts have failed to extract, and in which severe iriti> is 
present, even if sight is not destroyed. 

3. An eye the vision of which has been destroyed by plastic 
irido-cyclitis, or one which has atrophied or shrunken, provided 
there is tenderness on pressure in the ciliary region and attacks 
of recurring irritation ; or without waiting for signs of irritation. 

4. An eye whose sight has been destroyed, even though sym- 
pathetic inflammation has begun in the sympathizing eye, in the 
hope of removing a source of irritation and thus rendering treat- 
ment to the second eye more effectual. 1 

5. Au eye in which the wound has involved the cornea, iris, 
or ciliary region, either with or without injury to the lens, and 
in which persistent sympathetic irritation in the fellow eye has 
occurred, or in which there have been repeated relapses of sym- 
pathetic irritation. 

1 This rule is not adhered to by some surgeons, because it is believed by them 
that no good results will follow, but there is no proof that the practice is harmful. 



SYMPATHETIC IMPIiAMMATION. 341 

6. An eye cither primarily lost by injury or in a state of atro- 
phy, associated with Bigns of sympathetic irritation in the fellow eye. 

It is universally conceded that the enucleation of an eye (pre- 
ventive enucleation) primarily injured, the visual function of 
which cannot be restored, is the surest* way of preventing sym- 
pathetic ophthalmitis. It is to be remembered, however, that 
eveo a very early enucleation does not nece-sarily prevent sym- 
pathy in the fellow eye, because the infective process may have 
begun before the operation, and may not develop for several 
weeks. In place of enucleation, evisceration has been practised, 
but has also been followed by sympathetic inflammation ; neither 
does resection of the optic nerve (neurectomy) afford absolute 
security, but if the patient declines enucleation it should be 
used as a substitute. 

If sympathetic inflammation has begun, the rules just quoted 
are not applicable, and enucleation must not be performed if 
there is any vision in the exciting eye, which in the end may 
prove to be the more useful organ. The same principles of 
treatment already enunciated in regard to iritis and irido-cyclitis. 
are applicable. 

In the treatment of the sympathetically affected eye. operation 
usually has no place. Both iridectomy and sclerotomy have been 
advised, but it is better to await the subsidence of acute symptoms 
before attempting any surgical interference unless the intraocular 
tension be inordinately raised, and then scleral incision may be 
practised. 

The general treatment consists in confinement in a darkened 
room (moderate exercise with eyes well bandaged, is permissible in 
subjects failing for lack of it) ; complete functional rest of the eyes 
and atropine locally, provided there is no rise of tension and no 
atropine irritation ; and leeches to the temple, if the inflammation 
is florid. In robust subjects mercurial inunctions are useful ; in 
more debilitated cases a course of tonics and alteratives is advis- 
able ; under any circumstances full doses of quinine should be 
exhibited. Intraocular injections of bichloride of mercury should 
not be employed. Subconjunctival injections have been recom- 
mended. The author's experience with them in this disease has 
not been encouraging. 



342 DISEASES OF THE EYE. 

Under such treatment the affected eye will either recover with 
useful sight, pass into atrophy or phthisis bulbi, or grow quiet, 
with the formation of complete annular adhesions of the iris to 
the capsule of the lens, which has become cataractous. 

To improve visiou under the last-named condition, iridectomy 
and iridotomy have been tried, but the results are usually un- 
favorable. Extraction of the cataractous lens, with iridectomy, 
also presents serious difficulties. For those cases in which a 
transformation of the iris, lens, and capsule into a tough, opaque 
and inelastic tissue has occurred, Mr. George Critchett proposed 
and practised the following operation : The patient is placed 
under the influence of an anaesthetic, a speculum is introduced, 
the globe is fixed, and a fine cutting needle is introduced through 
the cornea, its point being directed to the centre of the capsule. 
This structure is penetrated by making a rapid rotary movement, 
on the principle of a gimlet. A second needle is introduced 
from the opposite side and the points separated from each other, 
the result being a rent in the centre of the capsule and the 
escape of the soft lens matter. The operation must be repeated 
at proper intervals until a clear pupil has been obtained. It is 
suited to young eyes. Care should be taken to avoid wounding 
the iris. The same operation is advised by Mr. Story. 

Peognosis. — The prognosis of sympathetic ophthalmitis is 
essentially grave. In some instances recovery occurs ; this has 
been seen in those cases in which neuro-retinitis is present, 
which, according to Schirmer, never begins after removal of the 
exciting eye, and is cured by enucleation, not immediately, like 
sympathetic irritation, but in the course of several days. 

More frequently, especially in the forms which appear as an 
irido-cyclitis or irido-choroiditis, the sight of the eye is lost and 
the organ shrinks. The varieties which appear as a serous iritis 
give the greatest hope for a good result. It is extremely import- 
ant to warn patients of the grave nature of this malady, and if an 
attempt is made to save an eye injured in the way already described, 
it must be done with the full understanding of the serious risks 
which are undertaken, and the patient kept under constant obser- 
vation. 



DISEASES OF THE CHOROID. 343 



CHAPTER XI. 

DISEASES OF THE CHOROID. 

Congenital Anomalies. — Two striking congenital anomalies 
occur in connection with the choroid : — 

1. Coloboma of Choroid is a large defect in the choroid, almost 
always in its lower part, and often associated with a similar vice 
of conformation in the iris. 

Examined with the ophthalmoscope the deficient area appears 
as a glistening pearl-colored patch, often irregular on its surface, 
owing to the development of several protrusions and correspond- 
ing intervening depressions, and bordered by an irregular pig- 
ment line. The retina may be recognized as a translucent veil 
covering the defect, and the retinal vessels occasionally pass into 
the depressions. The coloboma may include the optic nerve en- 
trance, either partially or completely, or may be separated from 
it by a bridge of healthy choroid. It may be confined to the 
area around the disc, or pass downward as far as it can be fol- 
lowed, and be connected with a similar defect in the iris from 
which it is separated by a band of choroid tissue. 

Coloboma of the choroid is seen also without coloboma of the 
iris. It is due to imperfect closure of the ocular cleft (choroidal 
fissure). 

In addition to coloboma in the usual situations, similar defects 
have been described in the macular region (macular coloboma, Fig. 
Ill) and the nasal half of the eye-ground (B. A. Randall and the 
author), and for these defects, which do not involve the optic disc, 
Lindsay Johnson has proposed the name extra-papillary coloboma. 
.Macular colobomata have been explained on the theory of intra- 
uterine choroiditis, but Johnson thinks they present many points 
in common with cutaneous naevi, and may be looked upon as the 
atrophied remains of nsevoid growths in the choroid. 

2. Albinism, or u congenital want of pigment in the choroid 



344 DISEASES OF THE EYE. 

and iris, is a deformity met with both in a complete and incomplete 
form. 

The iris lias a pink, or pink and yellow appearance, due to the 
reflection of light from its own bloodvessels and from those of 
the choroid, which, in the most pronounced forms of the defect, 
can be seen with the ophthalmoscope, down to their finer branches. 
The anomaly is most marked in early childhood, is almost in- 
variably associated with lack of pigmentation in the hair, and is 
accompanied by nystagmus, amblyopia, and high grades of re- 
fractive defects. In many instances albinism has been observed 
in several members of the same family, and seems to be heredi- 
tary. The influence of heredity is denied by Gould. 

Hyperaemia of the Choroid. — It is extremely doubtful whether 
an ophthalmoscopic examination can demonstrate hyperaemia of 
the choroid, just as later we shall see that such a condition of the 
retina is difficult of diagnosis. An actual hyperemia could fairly 
be shown to exist, only by finding a real distension of the vessels 
of the choroid, which usually are invisible, and the congestion of 
the choroid, described with myopic or asthenopic eyes, and as the 
result of exposure to bright light and heat, is more often a figure 
of speech than a proven pathological condition. The student 
should be on his guard not to mistake an exposure of the cho- 
roidal vessels by absorption of the pigment epithelium, for a con- 
dition of hyperemia. 

Nevertheless, in eyes subjected to prolonged strain, the result 
of uncorrected ametropia, certain changes in the normal appear- 
ance of the fundus arise, which are usually described under 
the vague term " choroidal disturbance." We may assume 
hyperaemia, when the nerve-head presents distinct redness, which 
is imperfectly differentiated from the unduly flannel-red appear- 
ance of the surrounding choroid, or when the choroid, instead of 
exhibiting its usual uniform red color, has changed into what has 
been denominated a " woolly choroid," with faint dark areas in 
the periphery, indicating the interspaces between the choroidal 
vessels, and more or less pronounced retinal striation surrounds 
the disc. This is a familiar picture in many cases of " eye-strain." 

Treatment. — In this condition, often associated with the 
subjective symptoms of aching eyes, some intolerance of artificial 



DISEASES OF THE CHOROID. 345 

light, and distinct asthenopia, the eye should be atropinized, dark 
glasses should be worn, and when the irritable condition of the 
fundus has sufficiently subsided, a proper correction of the re- 
fractive error should be ordered. 

A- an adjuvant to the local use of the atropine, the internal 
exhibition of small doses of iodide of soda, bromide of potash, 
and fluid extract of ergot serve a useful purpose. 

Choroiditis. — Under the general term choroiditis, are included 
various types of inflammation of the choroid which may be (a) 
idiopathic; (b) part of the symptomatology of disorders in other 
portions of the uveal tract, or indicative of general disease; and 

(c) traumatic. 

Symptoms. — Certain symptoms, for the most part revealed 
only by the ophthalmoscope, are present : — 

1. Alteration in the uniform dull-red surface of the eye-ground 
caused by («) the absorption of the pigment epithelium ; (b) 
patches of pale-yellow color with ill-defined boundaries due to 
exudate (recent choroiditis) ; (c) patches of white color due to 
exposure of the underlying sclerotic (atrophic choroiditis) ; and 

(d) patches of black pigment, variously shaped, scattered over 
the fundus, and usually bounding the spots of atrophy (pigment 
heaping). 

2. Absence of external manifestations indicative of the deep- 
seated disease, except when acute and purulent forms, in which 
the diseased process is not localized in the choroid, are accom- 
panied by injection, chemosis of the conjunctiva, etc. 

3. Changes in the transparent media (lens, vitreous) by the 
formation of opacities, as a secondary result of the choroidal 
disease. 

Subjective symptoms peculiar to choroiditis do not exist. 

Pain usually is not present except in purulent forms, and in 
such varieties as may be complicated with iritis. 

Disturbance of vision is in direct relation to the situation of 
the lesions and the amount of atrophy. If the choroidal disease 
is peripheral, visual acuity may be unaffected ; if atrophic patches 
occupy the macular region, sight may be greatly diminished, or 
practically obliterated. It is remarkable, however, that even in 
extensive diffuse choroiditis good vision may still be present. If 



346 DISEASES OF THE EYE. 

the disease has caused secondary changes in the vitreous or lens, 
these add to the depreciation of visual acuity. 

Scotomata, both positive and negative, may be present. Con- 
traction of the field of vision is found in certain types of choroi- 
ditis, and especially if secondary atrophy of the optic nerve has 
occurred. 

Diagnosis. — This is readily made by observing with the 
ophthalmoscope, the appearances briefly summarized in paragraph 
1 of the general symptoms. 

Inasmuch as choroiditis, in the large majority of cases, is com- 
plicated with secondary retinitis, it is difficult to decide whether 
the pigment lies in the choroid or retina. If the pigment mass 
is covered by a retinal vessel, and at the same time is situated in 
a deeper layer than this, its position is judged to be in the 
choroid ; if the retinal vessel is covered by the pigment mass, 
and the latter is situated more anteriorly, its position is assumed to 
be in the inner surface of the retina, to which spot it has wandered 
through secondary involvement of the retina. Pigment charac- 
terized by a " lace-like pattern," or resembling bone corpuscles, is 
always in the retina. (Xettleship.) A commingling of these 
positions in the same eye-ground is common. 

Course, Complications, and Prognosis. — A choroiditis 
may be sudden in onset and pursue an acute course; for example, 
an acute choroiditis at the posterior pole of the eye resulting in a 
permanent myopia, or in the purulent forms of the disease. 

More commonly the course of choroiditis is slow and chronic. 
Beginning with exudation or hemorrhage, it passes by slow stages 
through the period of absorpffeion, atrophy, and pigment accumu- 
lation. It is by the last signs a former choroiditis is recognized, 
and the changes are called "old choroiditis," or " choroid o-reti- 
nitis." 

The following structures are liable to become involved during 
the course of a choroiditis: The retina, which from its intimate 
association with the choroid through the pigment epithelium, 
probably does not escape in any instance, and in many the asso- 
ciation of disease is so close that we apply the term choroido-reti- 
iiitis or retmo-choroiditis ; the optic nerve (choroiditic atrophy); 
the vitreous (vitreous opacities) ; the crystalline lens (posterior 



DISEASES OJP THE CHOROID. 347 

polar cataract); the iris (irido-choroiditis) ; and the sclerotic 

!>•<•/, rotieo-choroiditis). 

Thf prognosis in choroiditis is always grave, and although care- 
ful nursing may preserve sight, in many instances great loss of 
vision and entire blindness may ensue. Necessarily the prognosis 
as to vision depends upon the position of the disease and its re- 
lation to tlie macula. 

Treatment. — This in general terms demands perfect rest for 
the affected eye, l>lood-letting from the temple in the early stages, 
protection from glaring light, and the administration of altera- 
tives the iodides and mercurials, especially if there is any reason 
to suspect syphilis. Further details will be reserved for the sec- 
tions devoted to the several varieties of choroiditis. 

A- alnady stated, choroiditis may be acute or chronic, and, like 
iritis, has been divided, according to its pathological nature, into 
plastic, serous, ami purulent forms. In like manner, when the 
cause of choroiditis is definitely known, it is customary to indi- 
cate this in the terminology, e. [/., syphilitic choroiditis. 

For the present purpose choroiditis may be divided into super- 
ficial and deep choroiditis, and a well-recognized classification 
may be adopted, which places all forms under one of two heads : 
(1) Non-sy/ppurative exudative choroiditis, and (2) Suppurative 
choroiditis and irido-choroiditis. 

Superficial Choroiditis (Epithelial Choroiditis). — Instead of the 
general dull-red appearance of the eye-ground, the larger vessels 
may be manifest as rather broad, reddish, or yellowish-red stripes, 
which traverse the fundus in an interlacing manner, and between 
which are the dark intervascular spaces, many of them having 
a lozenge-shaped appearance. This is due to the absorption of 
the pigment epithelium and the capillary layer which lies just 
beneath it. 

In certain instances it is physiological, and is commonly seen 
in the periphery of eye-grounds, often by preference occupying a 
space down and in from the disc. 

It may be universal, the only portion of the eye-ground 
escaping being the region directly confined to the macula, and 
it then presents a striking picture to the ophthalmoscope. The 
larger vessels of the choroid stroma pass in a sinuous manner 



34<s 



DISEASES OF THE EYE. 



across the eye-ground, bringing out into distinct relief, the pig- 
mented connective-tissue cells of the choroid proper, which lie 
between them (consult Fig. 112, page 354). Such appearances 
are seen in myopia; in " stretching eyes," when hypermetropic 
refraction is diminishing or passing into myopic refraction ; in 
glaucoma ; and sometimes is associated with retinal conditions, 
for example, pigmentary degeneration. The atrophy in this case 
is superficial, and of itself does not disturb vision. 

Treatment. — An eye thus affected should be put at rest, its 
refractive error corrected under the use of atropine or similar 
mydriatic, and the patient be given an alterative. If this is an 
associated symptom in a glaucomatous eye, or one with pigmen- 
tary retinitis, the present directions do not apply. 

Deep Choroiditis — (1) Diffuse Exudate Choroiditis. — Instead 
of the normal red of the eye-ground the ophthalmoscope reveals 
white or yellowish-white plaques, sometimes separated by partly 
normal choroid, more often running into one another until a huge 
expanse of exposed sclera is seen throughout the fundus. 

Fig. 108. 




Diffuse exudative choroiditis, with ehoroido-retimtis (E. v. Jaeger). 



The white patches appear speckled because numerous pigment 
masses of black color are collected upon tliem, irregular in form, 



DISEASES OF THE CHOROID. 349 

sometimes gathered in lumps, sometimes assuming variously 
shaped groups. They lie beneath the retinal vessels for the most 
part, although usually pigment will be found collected upon these 
retinal vessels showing the participation of the retina in the pro- 
cess (choroido-retinitis). (Fig. 108.) In other patches the atrophy 
has not been sufficient to expose the glistening white sclera, and 
here will be found the appearances described in superficial 
choroiditis, namely band-like, orange-yellow, or light red vessels, 
freely anastomosing with each other, and, between them, the 
pigmented epithelium. In still other spots, it may be, that a 
yellowish exudate is evident, which is the earlier stage of what 
afterwards becomes an absorbed spot, surrounded and partly 
covered by black pigment heaping. 

In cases like this all the stages from yellowish extravasation 
to complete atrophy are visible. 

(2) Disseminated Choroiditis. — Another form, which may be 
looked upon, according to a classification adopted by some au- 
thors, as the circumscribed variety of the type just described, is 
that which is known as disseminated choroiditis. 

In this type, usually beginning in the periphery, but gradu- 
ally approaching the centre of the eye-ground, numerous round 
or oval spots surrounded by black margins are found. The 
white centre of the spot is the exposed sclera; the black margin, 
the altered pigment. Again, instead of a white centre there 
may be a single black mass, in its turn encircled by a yellowish 
ring. A very characteristic appearance arises when the spots 
assume a punched-out look, as if a sharp instrument had cut out 
the tissue down to the sclera, the margins of the incision being 
bordered with pigment. 

These spots of disseminated choroiditis vary greatly in num- 
ber, There may be only one or two, or the eye-ground may be 
dotted over with them. Between the spots the choroid tissue is 
comparatively healthy. Like the diffuse variety, the earlier 
stages of such spots consist in small, yellowish exudations, which 
gradually absorb, producing the atrophic marks which have just 
been described. The relation of the retinal vessels to the pig- 
ment epithelium is the same as in the previous variety. (Fig. 109.) 

Vitreous opacities are often present, either faint and floating, 



350 



DISEASES OF THE EYE. 



or large, string-like, and membranous. There may also be cata 
ract at the posterior pole of the lens. 



Fro. 109. 




Disseminated choroiditis (De Wecker). 

The optic nerve becomes affected in the later stages of this dis- 
ease and undergoes a species of atrophy to which the name of 
choroiditic atrophy has been applied. The edges of the disc are 
slightly hazy, the color a reddish-yellow, and there is contraction 
of the retinal vessels. 

Causes. — The cause of deep choroiditis, either diffuse or cir- 
cumscribed, is due to acquired syphilis in a great number of 
cases, and appears from six months to two years after the initial 
infection. Sometimes it is postponed to a much later period (ter- 
tiary period). Opacities in the vitreous increase the probability 
of syphilis, and although certain types have been looked upon as 
especially characteristic of this disease, it is not safe to attempt to 
make a diagnosis of syphilis simply by the appearances of any 
of the varieties of choroiditis. Disseminated choroiditis, choroido- 
retinitis, and secondary pigment-degeneration of the retina arc 
seen in children the subjects of hereditary syphilis. Choroid iti- 
due to acquired syphilis usually affects both eyes. 

A disseminated choroiditis (hereditary choroiditis), affecting 
both eyes, is occasionally encountered as a family disease iude- 



DISEASES OF THE CHOROID. 351 

pendently of syphilis, and associated with the disorders of the 
central aervous system (Hutchinson). 

A choroiditis quite undistinguishable from the forms described, 
may result from an injury. Patches of choroiditis are found in 
the eyes of children horn with cataract. Choroiditis is also at- 
trihuted to disturbances of nutrition, anaemia, chlorosis, and 
scrofula, and sometimes no cause can be found. 

Treatment. — This depend- upon the cause. If it is syphi- 
litic and the patient is robust, inunctions of mercurial ointment 
Bhould be practised, to be followed by iodide of potash. Later, 
a prolonged course of the bichloride of mercury with the tincture 
of iron is advisable. Subconjunctival injections of mercury have 
been recommended. Anaemia and scrofula require treatment. 

All close work must be forbidden ; the eyes should be pro- 
tected with dark glasses. 

Prognosis. — The prognosis is always a grave one ; it is best 
in the syphilitic cases. If there should be much opacity in the 
vitreous, pilocarpine sweats may be tried ; in old cases, strychnia 
and the galvanic current have been advised. 

Central Choroiditis is the name applied to choroiditis confined 
to the region of the macula. 

There may be an irregular patch of exudation, semi- or com- 
pletely atrophic, and bounded by pigment. This is recognized 
objectively by the ophthalmoscope, and subjectively by scotoma 
in the field of vision marking this region. 

Again, the macula may be occupied or surrounded by a large, 
white patch, the rest of the eye-ground being normal. This type 
i- sometimes known as senile areolar atrophy of the choroid (Fig. 
110). The area may be entirely circular and the deep vessels 
exposed, or they may be atrophied and converted into white 
lines. 

In the same region there is observed another variety of the 
disease, first described by Tay and Hutchinson as central senilt 
guttata choroiditis, marked by the appearance of numerous, white, 
glistening dots, somewhat resembling the earlier stages of albu- 
minuric retinitis (Nettleship), and always symmetrical, though 
sometimes an interval of time elapses before the implication of 
the second eye. The white spots are due to colloid degeneration 



352 DISEASES OF THE EYE. 

and calcareous formations in the choroid, and are associated with 
secondary involvement of the retina. Usually there are contrac- 
tion of the field of vision and negative scotoma. Large areas of 
colloid change may also occur without disturbance of vision (ver- 
rucosities of the choroid, Fig. 113). 

Fig. 110. 




Central choroiditis (De Wecker and Jaeger). The circular character of the patch 
and the exposure and partial atrophy of the deep vessels are well shown. 

It is important, if possible, to recognize all forms of central 
choroiditis before a cataract operation is performed. This may 
be suspected if there is imperfect central fixation for light, but 
really can be positively determined only when the cataract is still 
incipient and the ophthalmoscopic examination is possible. 

Causes. — Central choroiditis of inflammatory type may be 
caused by syphilis and also by blows upon the eye. Chronic 
atrophic choroiditis in this region is seen in myopia, and Gould 
has described macular choroiditis as the result of uncorrected 
ametropia -and insufficiency of the internal recti muscles, even 
in non-stretching eyes (" ametropic choroiditis"). Senile changes 
account for senile central choroiditis and the guttate variety. 

Treatment. — In the syphilitic variety the usual remedies 
are indicated. In types connected with refractive error, the 
best possible correction should be given and absolute eye-rest 



DISKASES OF THE CHOROID. 



353 



enjoined. In the senile varieties, both the ordinary and the 
initiate types, treatment appears t(» have no influence. 

Unclassified Forms of Choroiditis. — Besides the diseases of 
the choroid which have been described, others appear which can- 
not be definitely classified : 

Large patches of atrophy not located in special portions of the 
choroid, resulting probably from the absorption of former hemor- 
rhages, or, perhaps, tuberculous areas; hemorrhagic choroiditis oc- 

FlG. 111. 




Macular coloboma. Compare with Fig. 110. 

eurring, as pointed out by Hutchinson, especially in young men, 
and resulting in numerous spots of atrophy which are not readily 
distinguished from those of the syphilitic variety ; yellowish or 
other spots of choroidal disease, which have been attributed to 
the action of intense light or the glare of heat ; slight macular 
changes in the form of small yellowish or maroon-colored spots, 
sometimes with a few scattered pigment granules in the imme- 
diate vicinity of the fovea, which do not affect vision and are 
unnoted by the patient. These have been attributed by some 
authors to the influence of abnormal refraction, but are sometimes 
seen in association with transient albuminuria, and probably repre- 
sent small spots of degeneration, inclosed by a single capillary 
loop which has become impervious. 

Myopic Choroiditis. — Atrophy of the choroid, commonly of 



354 



DISEASES OF THE EYE. 



a local character, occurs in severe, or, as it has sometimes been 
called, malignant myopia, and is observed either in connection 
with, or surrounding, the nerve head. It is caused by the elonga- 
tion which occurs at the posterior pole of the eye, and receives 
the name posterior staphyloma. 

The term sclerotico-choroiditis posterior is also applied to this 
variety of choroidal change, just as anterior sclerotico-choroiditis 
is the name given to the inflammatory affection, which attacks 

Fig. 112. 




Myopic choroiditis ( De Wecker and Fuchs). The cut illustrates posterior staphy- 
loma — the white area surrounding the nerve ; atrophic choroiditis in the macula 
— the disseminated white patches in the central part ; and general exposure of 
the choroidal vessels by absorption of the retinal pigment epithelium. 

circumscribed portions of the anterior part of the choroid, with 
corresponding portions of the sclerotic, and which, in aggravated 
instances, may give rise to staphylomatous bulging, and gradual 
loss of vision by opacity of the vitreous and cornea (see page 304). 

Semi-atrophic and atrophic crescents (often inaccurately called 
"conus") also appear at the outer margin of the disc in astig- 
matic eyes, and in eyes undergoing change owing to the dis- 
tension of their coats from too close work, aggravated by imper- 
fectly or improperly corrected errors of refraction. 

In the macular region in myopia, there may be very decided 
semi-atrophic or atrophic patches having the general characteris- 



DISEASES OF THE CHOROID. 355 

tics of the spots already described, and greatly interfering with 
vision. The process begins in the form of small rents which 
gradually coalesce into an atrophic patch. In like manner, this 
area may be involved by a hemorrhage in progressive myopia, 
which after absorption leaves impaired vision, owing to the 
damage to the overlying retina. The vessels of the choroid are 
exposed by maceration aud absorption of the retinal pigment 
epithelium, causing the appearance described under superficial 
choroiditis (Fig. 112). 

Suppurative Choroiditis and Irido-Choroiditis. — Acute iritis 
occasionally becomes complicated with inflammation of the choroid 
(page 315), and a chronic type of irido-choroiditis, which tends 
to loss of vision and shrinking of the eyeball has been described 
(page 325). 

The present disease, however, is distinguished by a suppurative 
process between the retina and choroid, which extends into the 
vitreous, and spreads into the entire uveal tract. 

Symptoms. — There are cedema of the lids, chemosis of the 
conjunctiva, haziness of the cornea, inflammation of the iris and 
ciliary body, and, it may be, hypopyon. If there is sufficient 
transparency of the media, the purulent mass may be seen in the 
vitreous, giving the appearance of a yellowish reflection, when 
viewed by transmitted light. At first the tension is raised and 
the anterior chamber is shallow. 

In addition to these objective symptoms, there are severe brow 
pain, tenderness of the globe, loss of vision, and constitutional 
symptoms as chill and fever. 

The ultimate result depends upon whether the disease remains 
localized in the uveal tract and vitreous, or spreads to all of the 
tissues of the eyeball. In the former case the inflammatory 
symptoms subside, the pain lessens, the intraocular tension is 
lowered, and the eyeball gradually shrinks. 

In the latter case the inflammation spreads, the oedema of the 
lids and chemosis of the conjunctiva are intense, the pain severe, 
and the constitutional symptoms — fever, chills, nausea and vomit- 
ing — are very marked. The inflammation involves Tenon's cap- 
sule, and causes protrusion of the globe, which is pressed against 
the swollen lids until these can scarcely be separated on account 



356 



DISEASES OF THE EYE. 



of the swelling and oedema. Finally, rupture of the sclera or 
sloughing of the cornea occurs, the purulent matter finds a vent, 
the pain subsides, and in about six weeks the ball is soft, sight- 



Fig. 113. 




Colloid change in the macular region. 



less, shrunken and free from pain. This second outcome of 
purulent choroiditis is known as panophthalmitis, and the ulti- 
mate result as phthisis bulbi. 

Causes. — Purulent choroiditis is caused by the introduction 
of pathogenic microbes in the same manner as in purulent cyclitis. 
It is hence seen as the result of perforating wounds ; septic cata- 
ract extraction ; and sloughing ulcers of the cornea. 

Purulent choroiditis is also caused by embolism from a microbic 
area, e. g., in pyaemia, especially in puerperal sepsis, septicaemia, 
and endocarditis. A common cause is cerebro-spinal meningitis, 
especially in children, and it has also occurred in wasting diseases, 
in dysentry, measles, and especially in smallpox with corneal 
complication. Inflanmiation of the umbilical vein, and throm- 
bosis of the orbital veins are known to cause the disease. 

Prognosis. — This is bad, and almost invariably blindness with 
shrunken eyeball is the result of the inflammation. A few cases 
of recovery from suppurative irido-choroiditis following cerebro- 
spinal meningitis have been recorded. 

Treatment. — In the early stages antiphlogistic treatment may 



DISEASES OF THE CHOROID. 357 

be of service in robust cases — bloodletting from the temple, a 
sedative fever mixture, with sufficient morphia to relieve pain, 
and locally, frequently changed ice compresses. In later stages 
warm fomentations are better, a square of lint being soaked in 
heated bichloride solution ; and internally, opium and quinine in 
full doses. If there is much pain before spontaneous rupture 
has occurred, a free incision into the sclerotic will bring relief. 

Surgeons differ in regard to the advisability of enucleating the 
globe during the acute stages of panophthalmitis, some operators 
declining to perform excision under such circumstances, in the 
belief that meningitis is liable to follow, while others do not 
recognize such a danger, and do not hesitate to operate. 

Under these circumstances evisceration has been recommended 
because the channels leading to the brain membranes are not 
opened and micrococci are less liable to enter. But even after 
evisceration there may be a great accumulation of inflammatory 
products behind the scleral cup, and to these a vent must be 
given ; hence Xoyes advises that while certain cases of panoph- 
thalmitis should be treated to the termination of the suppurative 
process without operation, in the majority of instances, deep inci- 
sions, with or without enucleation, are the best method of relief, 
even when the svmptorns of meningitis have appeared. 

Tumors of the Choroid. — The most frequent neoplasm of the 
uveal tract, and, for the present purposes of description, of the 
choroid, is sarcoma. Most commonly it appears as a pigmented 
growth (melano-sareoma); more rarely without pigment (leuco- 
sarcoma). 

Sarcoma of the choroid, in the majority of cases, occurs 
between the ages of thirty-five and fifty years ; it is rare under 
the twentieth year. Men are more frequently affected than 
women, and the left eye is more apt to be affected than its fellow. 
The growth usually is circumscribed, in which ease it may or 
may not have a pedicle. Rarely, there is a diffuse sarcomatous 
infiltration of the choroid. 

Sarcoma may be either round or spindle-celled, and is subject 
to the ordinary degenerations of this form of tumor. Sarcoma 
of the choroid is almost invariably a primary growth ; but the 
choroid coat may be, though rarely, affected by a metastasis occur- 



358 DISEASES OF THE EYE. 

ring from a tumor in some other portion of the body, for example, 
the mediastinum (A. V. Meigs and the author). The tumor arises 
from the layer of the larger vessels, and its most usual situation is 
near the posterior pole of the eye, at the outer side of the optic disc. 

The life history of a sarcoma of the choroid has been divided 
by systematic writers into four periods : The first, the quiet 
period ; the second, the inflammatory period ; the third, the ex- 
tra-ocular period, or that stage when the growth bursts through 
the scleral boundary ; and fourth, the period of metastasis. 

In the first stage the diagnosis is difficult, as the disease 
resembles a detachment of the retina, this membrane being 
pushed forward by the underlying elevation, the whole being sur- 
rounded by a serous effusion. By carefully looking through this 
retinal covering the brownish mass beneath may be recognized, 
covered by irregular choroidal vessels, a point, however, not 
always ascertainable, if the original growth is of the non-pig- 
men ted variety. If the growth is situated far forward, it is 
sometimes possible to examine it by means of oblique illumination 
through a dilated pupil. There is a corresponding defect in the 
field of vision, and the sight of the affected eye is diminished in 
accordance with the situation of the tumor. Should this be 
peripheral, the central vision at this stage may not be seriously 
affected. 

In the next period of the history of this growth, or the inflam- 
matory or glaucomatous stage, symptoms of increased tension arise: 
pain in the brow, anaesthesia of the cornea, shallowing of the 
anterior chamber, and dilatation and tortuosity of the perforating 
episcleral vessels. Ophthalmoscopic examination is no longer 
possible, the localized detachment of the retina becomes general 
by increased serous effusion, the lens may become cataractous, and 
a severe irido-cyclitis may be set up, which in its turn may be 
the cause of a sympathetic irritation of the fellow-eye. 

As the growth continues, the sclera becomes ruptured and the 
surrounding tissues are involved (fungus-stage, or stage of epi- 
scleral tumors). It may pass backward into the brain, or 
secondarily affect the optic nerve, but more commonly the last, 
or metastatic stage (stage of generalization) develops, when dis- 
tant organs are attacked by growths of similar histological 



DISEASES OF THE CHOROID. 359 

character, the liver far more frequently than other organs, but 
also the spleen, intestines, and even the lungs. Metastasis to 
the liver need not necessarily be delayed until the tumor has 
burst, at least not visibly, through the scleral boundary. One 
of the most extensive cases of secondary sarcoma of the liver 
which has come under the writer's notice, was in connection with 
a small sarcoma of the choroid, in which there was no external 
manifestation, but in which a few fragments in the orbital tissues 
appeared to be of suspicions nature after the removal of the eye. 

Diagnosis. — It is necessary to differentiate the sarcoma of the 
choroid from glioma of the retina. To this reference will be 
made in a future section. 

In the early stages choroidal sarcoma may be mistaken for 
idiopathic detachment of the retina. In the former, the defect 
in the field of vision is more sharply circumscribed, the central 
vision less decidedly affected, and the ophthalmoscope reveals no 
tremulousness of the overlying retina. Sarcoma may also be 
mistaken for a solitary tubercle of the choroid. 

In the stage of increased pressure, the disease is to be distin- 
guished from glaucoma by observing the suddenness of the onset 
of inflammatory symptoms — in the latter disease without ante- 
cedent history of poor vision — and the fact that in the glaucoma- 
tous eye, there are remissions in the acute symptoms, and that 
the tension is somewhat amenable to the myotics. 

Prognosis. — The prognosis in this form of neoplasm is unfavor- 
able. It is usually stated that death will occur within five years 
after the appearance of the original growth, provided no operation 
has been undertaken in the earlier stages. The published statis- 
tics show that the duration of the first, or quiescent period, is 
from one and one-half to two years. If there is no recurrence 
within four years, after removal of the eye, this complication 
becomes unlikely, although exceptions to this rule have occurred, 
and recurrence has been noted even after seven years. 

If the operation has been delayed, there may be local recur- 
rence in spite of it, and, what is still more serious, metastasis to 
a distant organ. 

Treatment. — From what has been said, it is evident that the 
only treatment is enucleation, and this at as early a stage as pos- 



360 DISEASES OF THE EYE. 

sible. It may be necessary to remove the entire contents of the 
orbit. 

Rare forms of tumor of the choroid are the following: Cavern- 
ous angioma, telangiectatic sarcoma, angiosarcoma (Ward Hol- 
den), or adenoma, enchondroma, and sarcoma-carcinomatosum. 
The writer has examined one such case microscopically. 

Carcinoma of the Choroid. — Seventeen cases have been re- 
ported, six bilateral and eleven unilateral. Of the latter, eight 
were of the left eye. All instances except two have been 
metastatic after mammary carcinoma. 

Tubercle of the Choroid. — Tubercles appear in the choroid 
as yellowish-white spots, varying in size from one to one and 
one-half millimetres, occasionally larger, and usually, though 
not necessarily, associated with similar growths in the men- 
inges. Repeated examination is required for their detection, 
and even then they may escape observation, owing to their 
diminutive size (" choroidal dust"). They have been frequently 
found in post-mortem examinations. 

Tubercles known as miliary tubercles, are distinguished chiefly 
by their color, which has been described as of a dull, yellowish- 
white in the centre, encircled by an ill-defined rose-colored area 
(Horner). Usually there are no pigmentary changes in the im- 
mediate neighborhood, but pigment bodies may surround the 
nodules, if they are prominent (Bach). They are situated 
usually near the optic disc or in the macular region, and vary 
in number from three to six, or many more. 

Instead of the miliary growth, a single large tubercular tumor 
may appear and progress, producing the same destructive changes 
that a sarcoma would originate, from which, indeed, it is very 
difficult to distinguish it. Such a growth may be associated with 
a similar one in the brain. 1 

Treatment. — Miliary tubercles of the choroid do not require 
any treatment directed to the eye itself, the vision of which may 

1 Chronic choroidal tuberculosis is characterized by optic neuritis, optic atrophy, 
hemorrhages (tuberculous inflammation), and a diffuse, yellowish-white discolor- 
ation occupying a considerable area of the eye-ground, within which are round, 
yellowish-white spots. Michel describes tuberculous granulation tumors of the 
choroid, which begin with the appearance of retinal detachment, and later cause 
abscess in the vitreous and shrinking of the eye. 



DISEASES OF THE CHOROID. 



361 



not be seriously affected. If a single large choroidal tumor were 
recognized, and the patient's general condition permitted it, enu- 
cleation to avert general tuberculosis is recommended. 

Injuries of the Choroid — Wounds of the ( 'horoid. — Necessarily 
in a perforating wound of the sclera, the choroid is also lacerated 
or incised, and no description other than that already given in 
this connection is required. 

Foreign Bodies in the ('horoid. — A penetrating foreign body 
may lodge in the choroid, and then the treatment described on 
page 306 is applicable. 

Rupture of the Choroid. — The most important injury to which 
the choroid is subject, and which follows a blow upon the eve, is 

Fig. 114. 




Rupture of the choroid. 



(From a patient under the care of Dr. Randall in the 
Children's Hospital.) 



rupture. This generally manifests itself in a sickle-shaped cres- 
cent, commonly on the temporal side of the disc, rarely on the 
nasal side, and very seldom extends in a horizontal direction. 
The rupture may be single or multiple, and sometimes is com- 
posed of several branches. The immediate effect of the blow is 
a hemorrhage preventing distinct observation. When this has 
disappeared, the fissure is evident to the ophthalmoscope as a 
yellowish-white stripe bordered with some disturbed pigment. 
(Fig. 114.) 



362 DISEASES OF THE EYE. 

The ruptures run concentrically with the papilla. They may 
be either complete or incomplete, and may, or may not, be asso- 
ciated with breakage of the overlying retina. In rupture con- 
fined to the choroid, the retinal vessels pass over it. If the retina 
has also given way there is apt to be more hemorrhage than 
without such accident, and no retinal vessels are observed crossing 
the choroidal separation. 

The ultimate result to vision depends upon the size and situa- 
tion of the rupture. At first there is very considerable loss of 
vision, partly due to effusion, and partly to injury of the iris, 
sometimes associated with blood in the anterior chamber. This 
slowly clears away, and very good vision may result, provided 
the change in the eye-ground has not been extensive. A de- 
terioration of vision may occur a long time after such an injury, 
owing to secondary changes in the optic nerve. 

Treatment. — The pupil should be dilated with atropine ; if 
there is much pain, a leech or two should be applied to the temple, 
a pressure bandage adjusted, and the patient put to bed. These 
measures suffice to encourage the absorption both of the blood 
and of the serous effusion. 

Hemorrhage into the Choroid. — In the section on unclassified 
forms of choroidal disease, variously-shaped hemorrhages which 
appear in this membrane, and which by absorption give rise to 
atrophic spots, have been described. In like manner there may 
be hemorrhage from the choroid, the result of a blow. A cho- 
roidal hemorrhage may be distinguished from one situated in 
the retina by noticing the more diffuse character of the extrava- 
sation and the fact that the retinal vessels pass over it, but the 
diagnosis is difficult. 

Detachment of the Choroid. — This is a rare condition. It 
may be idiopathic or traumatic, partial or complete. The prob- 
able cause of detachment would be by blood, serum, a layer of 
lymph, or a new growth. Cases following cataract extraction 
have been reported. 

Ossification of the Choroid. — This is occasionally found in 
eves long blind and shrunken from destructive irido-choroiditis. 
The formation of bon» occurs in the inflammatory tissue, and 
may be recognized by palpation in the form of an irregular plate, 



DISEASES OF THE CHOROID. 363 

spicule, or complete shell. Calcareous degeneration is common 
in eyes of this character. The eyeball should be enucleated. 

Atrophy of the Eyeball is a condition characterized by 
diminution in the size of, and alteration of the shape of, the 
globe, caused by contraction of inflammatory exudates, for ex- 
ample those formed in the uveal tract. It should be sharply 
distinguished, according to Fuchs, from phthisis bulbi, which 
results from a suppurative inflammation (see page 355) and is 
associated with rupture of the sclera and partial evacuation of 
the ocular contents. The former may give rise to sympathetic 
irritation; the latter usually (but not always) is harmless. 

Essential Phthisis Bulbi (ophthalmomalacia) is the name 
applied to a condition of the eye characterized by hypotony 
(softening) and diminution in its size which is unrelated to in- 
flammation. There may be photophobia, pain, myosis, and par- 
tial ptosis. An intermittent variety has been described. It may 
follow injury and be connected with disease of the sympathetic. 



364 DISEASES OF THE EYE. 



CHAPTER Xil 

GLAUCOMA. 

Glaucoma 1 is the name applied to several varieties of a dis- 
ease of which increased intraocular tension is the most character- 
istic sign. 

Varieties of Glaucoma. — (1) Primary glaucoma, or that 
form which arises without antecedent disease of the eye, and (2) 
Secondary glaucoma, or that form which occurs as the sequel of 
a pre-existing ocular disease, often an inflammation of the uveal 
tract. 

Primary glaucoma is acute, subacute, or chronic, and is further 
subdivided into inflammatory or congestive, and simple, or non-in- 
flammatory, non-congestive glaucoma. 

Symptoms. — The following is a syllabus of the symptoms 
common to the disease glaucoma, though not constantly present 
in each variety : — 

(1) Rise in intraocular tension, or increased hardness of the 
eyeball, varving from T? ("stiffened sclera") to T + 3 ("stony 
hardness"). In the former a positive rise of tension may be 
doubtful, the sclera simply presenting more than the usual re- 
sistance to the palpating finger ; in the latter, firm pressure fails to 
produce impression. Intermediate degrees are T + 1 and T + 2. 

This increased hardness of the eyeball may be measured by an 
instrument known as a tonometer, but in practice is estimated by 
palpating the globe with the finger tips in the manner described 
on page 90. 

1 The name is derived from the Greek word y\auxoc meaning sea-green, he- 
cause at one time this disease was known only by one of the signs of its 
final stages, viz., a greenish-yellow discoloration seen through the dilated 
pupil. According to Snellen, the characteristic symptom of glaucoma — in- 
creased hardness of the globe — wa3 first properly recognized by Mackenzie in 
1830. 



GLAUCOMA. 365 

(2) Change in the Size, and Shape of the Pupil and Mobility of 
tht Iris. — The pupil may be round, oval, or egg-shaped, semi- 
dilated, or expanded to its fullest limit ; the iris sluggish in 
movement, or entirely inactive. In simple glaueoma abnormal 
pupillary symptoms may be absent. 

The pupillary space sometimes transmits a greenish reflex 
(hence the name given by the older writers) from the surface of 
the lens. The dilatation of the pupil is explained by paresis of 
the ciliary nerves, or by constriction of the vessels of the iris. 

(3) Loss of the Transparency of the Cornea. — The cornea some- 
what resembles the appearance of glass, the surface of which has 
been dulled by being breathed upon. This haziness is marked in 
the congestive types of glaucoma, but is absent or only slightly 
'present in the simple varieties. If the cornea is carefully ex- 
amined, the cloudiness will be found more decided in the centre, 
and will resolve itself into very numerous closely-aggregated 
points, the whole presenting a stippled or " needle-stuck" ap- 
pearance. Iritis and irido-choroiditis may produce a similar ap- 
pearance (Schweigger). The condition is caused by oedema of 
the cornea. 

4 Change in the Depth of the Anterior Chamber. — This 
symptom varies from an almost imperceptible shallowing to a 
complete obliteration. While it is not customary to divide the 
various grades of narrowing of the anterior chamber into de- 
grees, as has been done with tension, such a division might 
include doubtful loss of depth, moderate loss, great narrowing, 
and complete obliteration. During the course of glaucoma the 
lens-system and peripheral portion of the iris are pushed for- 
ward, and this causes the depreciation in the depth of the ante- 
rior chamber. 

(5) ( 'hange in the Normal Appearance of the Iris and Turbidity 
of the Aqueous and Vitreous. — The same oedema which affects the 
cornea, may also cause loss in the characteristic markings of the 
iris, so that its pattern becomes indistinct, especially in congestive 
forms of glaucoma. The veins of the iris may be dilated and 
tortuous. Opacities in the media also are liable to form, and the 
lens itself mav become cataractous. 



366 DISEASES OF THE EYE. 

(6) Alterations in the Conjunctival and Episcleral Vessels. — In 
acute glaucoma there are usually general hyperemia and often 
oedema of the conjunctiva, but in chronic inflammatory, and even 
in simple glaucoma, there are marked enlargement and tortuosity 
of the episcleral venous branches. (System II., page 61.) 

(7) The Excavation of the Nerve-head and the Surrounding 
Yellowish "Halo" or "Glaucomatous Ring." — Under the influence 
of the increased intraocular pressure, the most impressionable 
portion of the eye — the intraocular end of the optic nerve — gives 
way, and the glaucomatous cup is produced. 

The cupping of the optic disc is seen with the ophthalmoscope, 
and its depth is measured according to the directions given on page 
120. It is also recognized by employing the parallax test with 
the indirect method as follows : The optic nerve is found in the 
usual manner by the inverted image, and the object lens moved 
from side to side. The entire eye-ground apparently moves 
with the motions of the lens, and the bottom of the excavation 
also seems to move in the same direction, but at a much slower 
rate. The contrast in the rate of the two movements is in a 
direct ratio with the depth of the excavation. 

The cup varies from one beginning to be pathological to a fully 
formed excavation. In the latter instance the excavation is com- 
plete to the scleral margin, and its edges are abrupt ; the vessels are 
crowded to the nasal side, bend sharply over the margin, and are 
lost to view behind the border of the cup, reappearing in fainter 
color at its bottom. 

The papilla is encircled by a yellowish ring due to atrophy 
of the surrounding choroid. 

It is important to distinguish between a large physiological 
cup, an excavation due to atrophy of the optic nerve, and the 
glaucomatous cup. A physiological excavation is partial and 
formed in a normally tinted nerve-head ; an atrophic excavation 
is complete, shallow, and formed in a nerve-head of abnormal 
whiteness owing to its loss of capillarity ; and a glaucomatous 
excavation is complete, deep, and often of greenish hue. (Consult 
fig. 115.) 

These points apply to typical forms of each variety of excava- 
tion. Sometimes it is a matter of considerable difficulty to 



GLAUCOMA. 307 

decide between them, especially between an atrophic and a glau- 
comatous excavation when the latter is shallow; or between a 
physiological excavation and glaucoma, when the former is asso- 
ciated with primary optic-nerve atrophy (Schweigger). A diag- 
nosis must then be based upon an examination of the other 
symptoms, particularly the field of vision. 

Fig. 115. 




Varieties of excavations in the nerve-head. A. Physiological excavation — par- 
tial, funnel-shaped, lamina cribrosa normal. B. Atrophic excavation — saucer-, 
shaped, total, lamina normal. C. Glaucomatous excavation — total, ampulliform, 
lamina pressed backward (Fuchs). 

(8) Vessel -Pulsation on the Surface of the Disc. — (a) The veins. — 
There is often marked venous pulse, especially at the dark 
knuckles of the veins as they bend over the margin of the exca- 
vation, but this is a common ophthalmoscopic appearance in 
healthy eyes (page 110), and hence cannot be utilized as a diag- 
nostic symptom. 

(b) The arteries. — Pulsation of the arteries is a rare appearance 
except in aortic regurgitation, and therefore may be regarded as 
an important indication of increased intraocular tension, in high 
degrees of which it is a striking symptom, the arterial trunks on 
the surface of the disc showing rapid alternate filling and collapse. 
It is usually, but not always, confined to the disc. The cause of 
spontaneous arterial pulsation resides in the resistance to passage 
of the blood through the vessels, a resistance which in turn de- 
pends partly upon increased tension and partly upon spasmodic 
contraction of the vessels themselves. In cases of glaucoma in 



368 



DISEASES OF THE EYE. 



which this pulse is not spontaneously visible, it may be induced 
by slight pressure upon the globe. 



Fig. 116. 



B 




temporal 



Glaucomatous excavation of the optic papilla. A, Ophthalmoscopic picture of 
the papilla. B. Vertical section through the nerve-head (figure and description 
after Fuchs). 

In the upper figure, A, the papilla is seen to be bordered by a sharp, over- 
hanging margin, at which the arteries a and the veins v appear to terminate in 
rounded ends. Their continuation to the bottom of the excavation is somewhat 
displaced toward the side. At the outer half of the excavation the stippling of 
the lamina I is visible. The papilla is bordered by a white zone h — the glauco- 
matous halo. 

In the lower figure, I>, the nerve-head exhibits a deep excavation, e, upon tin- 
floor of which a few remains of nerve fibres, b, are noticeable. The central vessels, 
c, proceed upward to the retina on the nasal side of the excavation ; ch indicates 
the choroid, s the sclera. The nerve trunk has lost in volume owing to atrophy 
of its fibres, n. On account of this the spaces between the sheaths of the optic 
nerve have widened, p, ar, and d. 

The student will more readily understand the objective symp- 
toms of glaucoma described in the preceding paragraphs by ex- 
amining figure 11 G. 



GLAUCOMA. 369 

In addition to the objective signs of glaucoma just described, 
certain subjective symptoms art- more or less constantly present. 

1. Pain. — This, like the disease itself, may be acute, subacute 
and chronic, somewhat, though not by any means exactly, corre- 
sponding to the types of glaucoma thus designated. 

In acute attacks the pain is a severe neuralgia of the trigeminal 
distribution, and often, in violent congestive cases, an intense 
agony associated with great depression, pallor of the countenance, 
nausea and vomiting. 

In subacute attacks there is a less marked similarly located 
pain. 

In chronic cases there may be only a general feeling of dis- 
comfort, a sense of fulness, occasional shoots of neuralgia, or 
attacks described by the patient as headache. 

'2. Alteration in the Sensibility of the Cornea. — Anaesthesia of 
the cornea, when present, varies from a slight depreciation in its 
sensitiveness to an entire loss of sensation, as complete as that 
produced by cocaine. A useful test is to take a wisp of cotton, 
twisted to a point, and stroke the surface of the cornea, comparing 
this with the unaffected eye, care being taken not to come in 
contact with the eyelid. Sometimes the anaesthesia is not 
uniform over the surface of the cornea, but exists in spots or 
segments. It is due to the oedema of the structure, which presses 
upon the filaments of the corneal nerves. 

•".. Alterations in Central Visu<d Acuity. — This symptom varies 
considerably, and in chronic cases excellent sharpness of sight 
may be preserved for a long time. It is important to remember 
this, because it is not safe to depend upon central vision as a 
guide of the rate of progress of a chronic glaucoma. In each 
attack of subacute glaucoma the vision quickly fails, and gradu- 
ally is recovered as the attack passes away. Each recurrence 
leaves a more permanent impression. In acute glaucoma, a 
characteristic symptom is the sudden loss of vision, which in a 
few hours may be reduced to a light perception, and in certain 
malignant types rapidly becomes absolute. 

4. Diminution of the Refractive Power of the Eye and of the 
Amplitude of Accommodation. — The former depends upon the 
change in the shape of the cornea, and the latter upon the effect 

24 



370 DISEASES OF THE EYE. 

of pressure upon the ciliary nerves. A very important event in 
chronic glaucoma is the changing of an astigmatism "accord- 
ing to the rule" to one " contrary to the rule," while the dimin- 
ished power of accommodation is evidenced by the desire of 
patients to change their reading glasses to such as are stronger 
than the degree of refractive error or age of life would warrant. 
5. Alteration in Peripheral Vision, or the Field of Vision. — A 
careful map of the field of vision in glaucoma is indispensable, 
and the restrictions present themselves in several forms : (a) The 
most usual and typical variety is partial or complete loss of the 
nasal field ; (b) concentric restriction of the entire field ; (c) re- 
striction so constituted that the remaining field assumes an oval 
or trowel shape ; (d) sectional defects, commonly including the 
upper portion ; (e) loss of the entire field except a patch on the 
temporal side ; (/) the formation of dark areas or scotomata. 
(Figs. 117-122.) 

Fig. 117. Fig. 118. 





Field of vision of right eye in a case Field of vision of right eye in a ca6e 
of subacute glaucoma. Loss of the of chronic glaucoma, showing con- 
nasal half and concentric restriction centric restriction of the field. 
of the preserved field. 

The contraction of the color fields is usually proportionate to 
that of the form field. Under the influence of operative measures 
or myotics very decided changes in the visual field may take 
place. The change in peripheral vision is a more accurate index 
of the rate of progress in glaucoma than central vision, but it is 
not a safe one. 



GLAUCOMA. 



371 



The tendency of the visual field is to contract progressively as 

the disease advances, and finally all portions are obliterated ex- 



Fig. 119. 




Field of vision in right eye in case 
of chronic glaucoma, showing sec- 
tional defect (supero-nasal quad- 
rant). 

Fig. 121. 




From the same case as Fig. 120, six 
months later; only a small patch of 
preserved field on the temporal side. 



Fig. 120. 




Field of vision of left eye in chronic 
glaucoma. Trowel-shaped patch pre- 
served chiefly on the temporal side. 

Fig. 122. 




Field of vision of the right eye in 
a case of chronic glaucoma, showing 
semi-annular scotoma. 



cept a small part upon the temporal side, which also disappears 
in the ultimate blindness, if the disease is unchecked. (Consult 
fig. 121.) 

6. Iridescent Vision. — This consists in variously-hued borders 
surrounding artificial lights, which thus become invested with a 
colored halo (" halo-vision"), the red circle being the outermost. 

This phenomenon has been attributed to various causes de- 
pending upon physiological or physical effects. Experimental 



372 DISEASES OF THE EYE. 

evidence tends to support the opinion that the cause resides in 
the cornea, and depends on alterations in its epithelium, the result 
of exaggerated pressure. 1 

Subjective sensations of light are experienced at times by 
totally blind glaucomatous patients. The explanation is proba- 
bly a mechanical one, and the sensation depends upon a dragging 
on the retina. In one case noted by the writer, both eyes being 
blind from glaucoma, the patient declared "all things seemed to 
be a sea of red fire." 

The clinical varieties of glaucoma may now be described. 

1. Acute Glaucoma (Inflammatory or Congestive glaucoma). 
— This type of the disease is suitably divided into two stages : — 

(a) Period of Incubation, or Prodromal Stage. — This is char- 
acterized by sudden failure in the amplitude of accommodation, 
with a desire to resort to stronger reading glasses ; temporary 
obscurations of vision, either dim vision or quite complete loss (if 
sight, lasting for many minutes ; attacks of foggy vision, all tilings 
apparently being invested with a haze; and the phenomena of 
colored halos around artificial lights. There may be some peri- 
orbital pain, the pupil is slightly dilated, and the cornea and the 
aqueous humor faintly turbid. The appearance of the optic nerve 
at this stage is not characteristic. 

These prodromes bear some relation to emotional excitement and 
insomnia, and may occur when the head is congested, or after a full 
meal. After the eye regains its natural state, in a week or two 
the symptoms may reappear, again to subside and to be replaced 
by a fresh exacerbation, or a true "glaucomatous attack." The 
incipient period of glaucoma may last one or more years. 

(b) Period of Attack, or the "Glaucomatous Attack." — This 
commonly begins during the latter part of the night, sometimes 
having been preceded by prodromes, but often without previous 
warning, and is characterized by violent pain in the head, so 
severe that it may induce nausea and vomiting. The face may 
be pallid, the extremities cold, or there may be flushing and 

1 According to Schweigger halo-vision occurs in mild attacks of iritis with 
slight deterioration of vision. It may also be caused by a layer of mucus 
overspreading the cornea during chronic conjunctivitis. 



GLAUCOMA. 373 

general fever. The eyelids are swollen, the conjunctiva injected 
and sometimes chemotic, the cornea steamy and anaesthetic, the 
pupil semidilated and motionless, the aqueous turbid, and the 
iii- discolored. The tension rises very high, T + 2 or + 3, and 
vision is rapidly lost, often only light-perception remaining, and 
even this may be abolished. Usually the attack is bilateral ; an 
interval between the two eyes may be from a few hours to weeks 
or month-. 

Gradually the symptoms pass away, with the exception of 
slight impairment in the mobility of the iris, some limitation of 
the field, and a little rise in tension. Blindness almost never 
occurs in the first onset. After some weeks or months these 
phenomena reappear. After a number of attacks, examination 
of the eye-ground during a remission (the fundus is not visible 
during an attack) may reveal the characteristic cupping, the halo, 
and the arterial pulse. 

If the disease is unchecked, the eye passes into a glaucomatous 
state, with fixed and dilated pupil, discolored iris, greenish reflex 
from the lens, vitreous opacities, shallow anterior chamber, and 
hazy cornea. Vision is now gradually destroyed and the eye 
reaches the state of absolute glaucoma, when the ball is stony 
hard, the iris atrophic, the lens eataractous and pushed forward, 
the anterior chamber obliterated, the sclera discolored, the episcleral 
vessels coarsely injected, the cornea opaque, or perhaps ulcer- 
ated. Finally, there is disorganization of all the structures of 
the eyeball, and the sclera gives way with the formation of 
staphylomata, or the eyeball slowly atrophies as the result of 
choroiditis, change in the vitreous, and detachment of the retina. 
Acute glaucoma, instead of pursuing this course, occasionally 
pa— e- into a chronic inflammatory type. 

Glaucoma fulminans is the name applied to an aggravated, rare 
form of the acute disease, in which the symptoms may be fully 
developed in a few hours without a prodromal stage. There is 
no remission, and the destruction of vision is swift and permanent. 

2. Subacute Glaucoma. — This type, like its predecessor, may 
or may not begin with certain prodromal signs. These, when 
present, become more pronounced and the eye gradually pass - 
into a .-tage characterized by the constant presence of a -cries of 



374 DISEASES OF THE EYE. 

symptoms which are best described under the title chronic inflam- 
matory glaucoma. 

The cornea is deficient in transparency or positively steamy ; 
there is marked tortuosity of the episcleral veins and some dis- 
coloration of the scleral tissue ; the aqueous humor is turbid and 
the deeper media present opacities ; ophthalmoscopic examina- 
tion, when it is possible, reveals the cupped disc and pulsating 
vessels ; the tension of the eye is raised ; the pupil is semi- 
dilated, and the iris sometimes atrophic and sometimes not. 
Hence two types of chronic inflammatory glaucoma are de- 
scribed, one associated with degenerative changes in the iris, 
and one without such association. 

The field of vision is contracted either upon the nasal side or 
a quadrant of the field is darkened. 

During the course of the disease acute or subacute attacks 
supervene ; that is, there are sharp ciliary pain, increased steami- 
ness of the cornea, increased injection of the eyeball, sinking of 
the vision, exaggeration of the tension, and marked anaesthesia 
of the cornea. The attack then passes away and in a few days 
or weeks repeats itself. Sometimes instead of a subacute attack 
of this character, an acute congestive exacerbation occurs, in all 
respects resembling the disease just described, and like it ending 
in absolute glaucoma, or in degeneration of the tissues of the 
eye. This disease may last from several months to a year. 

3. Chronic Glaucoma, or Non-inflammatory Glaucoma (usu- 
ally known as Simple Chronic Gkmeoma). — This type of the dis- 
ease is characterized by an absence of the signs of glaucoma in the 
anterior aspect of the eye, at least on ordinary inspection. By 
careful examination, slight steaminess of the cornea may some- 
times be detected, with a little lack of transparency in the aqueous 
humor. So, too, there may be some undue tortuosity of the 
perforating branches of the episcleral plexus. In general terms, 
however, there is an absence of congestive symptoms and there 
is no pain. The tension of the eyeball is but slightly increased, 
and often it is difficult to decide whether it is increased at all. 
The anterior chamber is not much shallowed. 

One or both eyes may be affected. If one eye is affected, then 
the pupil on that side is usually a little larger than its fellow ; if 



GLAUCOMA. 375 

both eyes are affected, the one more advanced than the other, the 
pupil will be slightly larger on the side of the greater disease. 
The central vision may be good, and in the earlier stages of the 
disease, after the correction of any refractive error, may reach 
nearly the normal standard. 

The media arc clear, and the disease is detected with the 
ophthalmoscope, by observing the characteristic cup in the nerve- 
head, the halo surrounding it, and the spontaneous arterial pulse, 
or its ready development by slight pressure. 

The field of vision gives important information. Usually the 
contraction is upon the nasal side, and this gradually increases 
and involves the fixing point. (Fig. 121.) The central color 
perception is good, and the contraction of the peripheral color 
perception corresponds with that of the form field. 

Simple chronic* glaucoma may assume a subacute or an acute 
nature like that already described, but it may also progress to 
blindness without very aggressive symptoms. 

Causes. — (a) Predisposing Causes : Primary glaucoma is rare 
before the fortieth year; not one per cent., according to Priestley 
Smith, begins earlier than the twentieth year. Of these a few, 
generally monolateral, are seen in children. Jews and Egyptians 
are said to be peculiarly liable to the disease. The glaucomatous 
eye is usually hypermetropic, although Priestley Smith's statis- 
tics do not indicate a striking preponderance of this refractive 
state. There is a relation between smallness of the cornea and 
glaucoma. The average horizontal diameter of the normal cornea 
is 11.6 mm., of the glaucomatous cornea 11.1 mm. (P. Smith. 
Story's measurements yield an average of 11.9 mm.). A large 
lens is a predisposing factor, and small eyes, in which the lens 
may be disproportionately large, are more liable to the disease 
thau normal globes, (b) Exciting Causes: Glaucoma may be 
excited in eyes predisposed to the disease by worry, insomnia, 
bronchitis, arterial sclerosis, heart disease, gout, and neuralgia of 
the fifth nerve. Sometimes it follows injury and hemorrhage 
into the uveal tract. Over-use of ametropic or improperly cor- 
rected eyes, by causing uveal congestion, may bring on glaucoma 
in an eye predisposed to the disorder. A number of instances 
have followed the instillation of the mydriatics, even cocaine. 



376 DISEASES OF THE EYE. 

Should a patient between his fiftieth and sixtieth year desire 
to change his reading glass frequently, or use one stronger than 
is suited to his age or the condition of the refraction of his eye, 
there is reason to apprehend the onset of glaucoma. On the 
whole the disease is slightly more common in women than in 
men. Those symptoms which have been described as prodromes 
are distinctive in themselves, and acquire an importance greater 
than any probable predisposition. 

Mechanism. — Von Graefe explained the nature of the disease 
by assuming an inflammatory process — a serous choroiditis — 
originating in changes in the bloodvessels, typified by the acute 
types. Donders regarded irritation of the trigeminus as the factor 
which gave rise to a hypersecretion of fluid, just as stimulation 
of the chorda tympani induces excessive salivation, and believed 
the acute types were the results of increased tension induced by 
vaso-motor influence. These theories were no longer tenable after 
the discovery of the nutrition processes and the path of the cir- 
culation of fluids in the normal eye. 

It has been demonstrated by Leber that the ciliary body is the 
chief secreting organ of the eye, and the current is thus described 
by Snellen : — 

"The freshly secreted fluid stands in close osmotic relation to that 
which is contained within the thin membranes of the vitreous body. 
A slight excretion of fluid occurs at the back of the eye from the vitre- 
ous body into the lymph-spaces of Schwalbe in the optic nerve. The 
chief stream passes over the lens and through the pupil into the ante- 
rior chamber, traverses the latter to reach the angle formed by the 
junction of the iris and the cornea, passes through the meshes of the 
ligamentum pectinatum, and by diffusion and filtration is taken up into 
the plexus of veins known as Schlemm's canal. There is no direct 
connection between the anterior chamber and the lymph-spaces, which, 
according to Schwalbe, exist in Schlemm's canal. The influence of the 
nervous system on the pressure of the- fluid is indirect. The pressure 
of the fluid regulates the outflow, so that when the afflux is increased, 
a compensatory increase of the efflux occurs." 

Knies and Weber demonstrated that in glaucomatous eyeSj 
with shallow anterior chambers, there is an adhesion of the iris- 
base to the periphery of the cornea, which prevents filtration at 
the angle of the anterior chamber, thus causing retention of 



(JI.AICOMA. 



::77 



fluid. (Figs. 123, 124.) This discovery developed the theory 

which is supported by the largest Dumber of advocates. Kuies 



Fig. 123. 




Angle of the anterior chamber in the normal eye. (Bimbacher.) 
Fig. 124. 




Angle of the anterior chamber in glaucoma closed by adhesion of iris-base to the 
periphery of the cornea. (Birnbacher.) 

believed that glaucoma originated in an adhesive inflammation of 
the iris-periphery, while Weber regarded this adhesion as sec- 
ondary to the pressure induced by an abnormally swollen ciliary 
body. The fact that a mydriatic does harm, by dilating the pupil, 
rolling back the iris, and partly closing the filtration angle, and 
that eserine does good, by contracting the pupil and drawing 
away the iris from this angle, indicates, as Snellen has pointed 
out, that the explanation of glaucoma is to be found, not in an 
increase of secretion, but in a disturbance of excretion. 

According to Priestley Smith, obstruction of the circumlental 
space (i.e., the space between the margin of the lens and the sur- 



378 DISEASES OF THE EYE. 

rounding structures) and consequent rise of pressure, may follow 
increased size of the lens due to advancing years, unusual small- 
ness of the ciliary area in hypermetropia, or abnormal enlargement 
of the ciliary processes. This observer believes that hyper-secre- 
tion is sometimes concerned in the onset of glaucoma ; that se- 
rosity of the fluids plays an important part in those forms which 
present a deep anterior chamber and wide filtration-angle ; and 
that obstruction at this angle is part of the glaucomatous attack 
in the vast majority of cases. 

Laqueur and other observers think that glaucoma depends upon 
obstruction of the intraocular lymphatics which find their way 
out with the vasa vorticosa, owing to rigidity of the sclerotic coat. 
Brailey describes a chronic inflammation of the ciliary processes 
and iris-periphery, with distension of the vessels, as the earliest 
lesion in glaucoma. Stilling believes that a hardening of the 
sclerotic surrounding the papilla, through which he thinks the 
waste fluids escape, leads to glaucoma. 

The influence of strain upon the accommodation is explained 
by Snellen as follows : In the young eye, during accommodation 
for a near point, the diameter of the lens is reduced to about the 
same extent as that of the contracting ciliary muscle. The cir- 
cumlental space remains about as wide as it was before, and the 
zonula remains tense as before. But the conditions are quite 
different in advanced life, when the elasticity of the lens is lost; 
the ciliary muscle contracts, but the form and size of the lens 
remain unchanged. The ciliary process is thereby pressed against 
the lens and the zonula slackened. Hence the necessity of cor- 
rection of refractive errors as a preventive measure. 1 

Diagnosis. — It is of the utmost importance that glaucoma 
should be recognized, if possible, in its very incipiency. The 

1 A translation of the Dutch original of Snellen's article, "A Historical 
Essay on the Development of our Present Knowledge of Glaucoma," which 
has heen quoted several times, is found in the Ophthalmic Review, Feb. 1891. 

Inasmuch as the theories in regard to glaucoma do not explain its mechan- 
ism in all cases, it is possible that later investigations may prove that it really 
is a " nervous affection." Dr. Knapp, in clinical lectures, has dwelt upon thf» 
remarkable liability of the Jews to this disease as a significant fact in this 
connection. They are an essentially neurotic race, and prone to other nervous 
diseases. 



<.i ai< oma. 379 

most usual prodromal symptoms, arc a frequent desire to change 
the reading glasses, periods of obscuration of vision, and the 
halo surrounding the lamp lights. 

The glaucomatous attack itself has frequently been mistaken 

f<»r a " cold in the eve," for iritis — when the disease has been 

:avated by the instillation of atropine, which under almost 

all circumstances i- contraindicated — for neuralgia, and for reflex 

ocular pain. 

The condition of the pupil, the diminished depth of the ante- 
rior chamber, and the increased tension of the globe, are the 
symptoms which should prevent so fatal an error. 

The differential diagnosis of simple chronic glaucoma and at- 
rophy of the optic nerve has been referred to and presents consid- 
erable difficulty. The occasional absence of increased tension in 
the simple form of the disease, or at least its doubtful presence, re- 
moves an important diagnostic point. Help maybe obtained by 
< il (serving the color fields. In glaucoma these present a restriction 
corresponding with that of the form fields, while in atrophy the 
peripheral color vision, especially for red and green, is markedly 
deficient. 

Examination of the light sense may be made. In glaucoma 
the " light minimum" is said to be deficient, but the " light dif- 
ference" not far from normal ; in pure optic atrophy there is imper- 
fect ability to distinguish between different intensities of illumina- 
tion ("light difference"). Practically, these examinations are 
difficult to make and the results are not always satisfactory. 

It is an inexcusable error to confound the failing vision of 
chronic glaucoma with that of cataract, the greenish reflex of 
the lens, which may be seen in the pupillary space, being mis- 
taken for an opacity of the lens. Eyes have been permitted to 
pass into blindness, and their possessors deluded with the hope 
that they were waiting for the ripening of a cataract which never 
existed. An ophthalmoscopic examination would settle the diag- 
nosis at once. 

Prognosis.— Glaucoma does not tend to spontaneous cure, 
but, if unchecked, to absolute blindness ; hence the prognosis is 
unfavorable if proper treatment cannot be applied. Prognosis 
also depends upon the type of the disease and the stage of its 



380 DISEASES OF THE EYE. 

development. Other things being equal, uncomplicated acute 
cases furnish the most reasonable hope of complete cure. la 
chronic cases much depends upon the amount of degenerative 
change in the tissues, and the prognosis must be guided by the 
state of vision, the extent of the field, and the condition of the 
iris. The effect of treatment upon the progress of glaucoma i> 
included in the following section : — 

Treatment. — In practically all cases of glaucoma some form 
of operation — by preference iridectomy — is needed to check the 
disease. 

It may happen, however, that an operation is not at once 
possible, and hence the myotics are temporarily indicated. In 
the prodromal stage eserine should be employed and will usually 
relieve the symptoms. In acute cases the same drug, in a strength 
of from one-half to two grains to the ounce, acts favorably, pro- 
vided the pupil will contract under its influence. It acts more 
efficiently when combined with cocaine. Pilocarpine in twice this 
strength may be substituted. Myotics act by drawing the iris 
away from the filtration-angle, and, by contracting the pupil, 
cause widening of the spaces of Fontana and absorption of the 
fluid. A drop or two of the selected solution should be in- 
stilled every hour or two until relief is obtained ; if this does 
not occur, the drug should be abandoned and an operation at 
once undertaken. 

In addition to the use of eserine during an acute attack, the 
temple may be leeched, warm fomentations applied, and rest and 
relief from pain secured by the exhibition of full doses of mor- 
phine and chloral, the latter drug having some influence in re- 
ducing tension. Advantage may further be gained by giving a 
purge and a sedative fever mixture. Medicinal treatment is 
only a temporary matter and must not be relied upon. 

In chronic inflammatory glaucoma and in the simple variety 
the indication for eserine, unless there are subacute attacks, i- 
not so clear. Still, if the tension is above normal, this drug, oi- 
ks substitute, may be employed until it is decided what opera- 
tion shall be done and when it shall be performed. The ener- 
getic use of eserine causes some irritation of the ciliary body ami 
spasm of accommodation, and, as has been stated, strain upon the 



GLAUCOMA. 381 

accommodation predisposes to glaucoma. Hence if eserine is to 
be used continuously it is better n<>t to employ it in a too strong 
solution (gr. -., i i — J— oj will suffice), and, in the belief of some sur- 
geons, pilocarpine is preferable. This congestion of the ciliary 
processes induced by eserine, sometimes entirely defeats its 
proper action. Another point, although a minor one, is that 
its continuous use tends to cause a follicular conjunctivitis in 
some eyes. 

Iridectomy is the best method of treating glaucoma. General 
anaesthesia should be induced before its performance, because the 
high tension of the eyeball somewhat nullifies the action of cocaine. 
Much depends upon the exact position of the iridectomy, which 
is difficult of performance on account of the narrow anterior 
chamber, and no caution should be omitted which will secure 
perfect quiet on the part of the patient. 

The following points must be observed : (1) About one-fifth 
of the iris should be excised, the detachment being made up to 
the periphery by cutting first one side of the portion of the iris 
which has been drawn out of the wound, then dragging it across 
to the other angle and completing the excision, thus removing 
everything up to the ciliary border. (2) The wound should be 
sufficiently large to permit of such extensive detachment of the 
iris. (3) The point of selection for the entrance of the keratome 
should lie in the sclerotic coat about 2 mm. from the apparent 
border of the cornea. (4) The knife should be withdrawn slowly 
in order to prevent a sudden gush of aqueous humor, and a too 
rapid reduction of tension which might be followed by intraocular 
hemorrhage. (5) Great care must be taken that no portion of the 
excised iris remains in the angles of the wound. (6) A prelim- 
inary scleral puncture in cases of exceptional gravity is advised 
by P. Smith and Gifford. 

A favorable result is indicated if the tension is lowered; an 
unfavorable one if this remains high. If there is a sudden rise 
of tension a short time after the operation, accompanied by severe 
pain, there is reason to suspect intraocular hemorrhage. 

The cutting of the iris is often followed by an extensive hem- 
orrhage into the anterior chamber. A prolonged effort to get 
rid of this blood should not be made lest the trituration produce 



382 DISEASES OF THE EYE. 

cataract. The blood will absorb, although it may take many 
days and even weeks before this is entirely accomplished. 

The reforming of the anterior chamber is sometimes delayed 
as long as a week. Occasionally, a day or two after the operation 
there is some slight rise of tension in the eye, which is of tempo- 
rary character. 

There is difference of opinion in regard to whether the eye 
should be bandaged or not, after operations of this character. 
The author believes that not only should a bandage be applied, 
for the first few days, to the eye upon which the operation has 
been done, but also to the fellow eye ; and that the one placed 
upon the affected organ should remain there until complete re- 
storation of the anterior chamber has taken place by healing of 
the wound. In most instances it is best to perform the iridec- 
tomy directly upward, so that the overhanging upper lid may 
cover the coloboma. It may be necessary, in the event of one 
iridectomy failing, to repeat the operation. It is a wise precau- 
tion to instil eserine into the eye which has not been operated 
upon, during the course of the treatment. 

One of the complications which may follow the operation of 
iridectomy in glaucoma, is the formation of a bulging scar at 
the seat of incision, sometimes called a cystoid cicatrix. This is 
especially true if due care has not been taken to free the angles 
of the wound from adherent iris. On the other hand, in bad 
cases, this very cystoid cicatrix, by permitting a filtering of the 
liquids, has been looked upon as a favorable condition. 

The treatment of chronic inflammatory glaucoma and simple 
glaucoma by iridectomy is less likely to be followed by brilliant 
results than in acute cases ; and numbers of instances are on 
record in which after the performance of an operation, entirely 
correct in its technique, the disease has not been stayed. Depre- 
ciation of vision may occur, partly due to the astigmatism which 
lias been produced by the operation. 

An operation should be done before much contraction of the field 
has occurred. Some surgeons, for example Nettleship, believe that 
the state of the pupil and its reaction to eserine furnish a good 
prognostic guide for operative interference in chronic glaucoma. 

The conclusions of Gruening in regard to this matter are as 



GLAUCOMA. 383 

follows : In chronic inflammatory glaucoma without a degenera- 
tive change in the iris, a satisfactory result follows a careful 
iridectomy. If, however, there is degenerative change in the iris, 
iridectomy does not give the desired relief. In simple glaucoma 
iridectomy generally maintains the condition of vision which 
was present before the operation, other things being equal, and 
consequently is a proper surgical procedure. 

Even if there is a good deal of contraction of the field, and the 
optic disc quite pale (provided the patient is not too far advanced 
in life), it is proper to attempt an operation, especially if both 
eyes are affected. Bull's advice, after all the chances of suc- 
cess and failure have been fairly stated, is " to operate in cases 
of chronic progressive glaucoma, and the earlier the better." 
Schweigger teaches that it is advisable to operate in chronic 
glaucoma affecting both eyes, first upon the worse one, even if 
it is blind. Should the healing process be normal, the second 
eye may be operated upon without fear. 

Other operations for the relief of glaucoma have been prac- 
tised and with alleged good results. Thus, repeated paracentesis 
of the cornea will relieve the tension, but gives only temporary 
results. Trephining the cornea has been tried, and stretching 
the external nasal nerve was introduced by Badal, and may suffice 
to relieve pain, being sometimes applicable in cases of blind eyes 
in which it is desirable to avoid the operation of enucleation. 

The operation of sclerotomy has been used as a substitute for 
iridectomy, but the weight of testimony in favor of the latter 
operation is sufficiently great not to make this a desirable mode 
of procedure except in selected cases. Every iridectomy which 
is peripherally situated, and in which the knife enters through 
the sclera some distance from the apparent border of the cornea, 
is in itself a sclerotomy. It is useful as a supplement to iridec- 
tomy if the tension is not reduced, and may be employed in old 
blind glaucomatous eyes to relieve paiu. 

It is not entirely certain how iridectomy cures glaucoma. It 
has been suggested that this is accomplished by the removal of 
the portion of tissue which closes the angle at the anterior cham- 
ber ; by the moderation of the blood pressure in the iris (Exner) ; 
or by the filtration of the fluids of the eye, through the line of 



384 DISEASES OF THE EYE. 

healing, which, for this reason, has been called the filtration scar. 
The details of performing iridectomy and sclerotomy will be de- 
scribed in the chapter devoted to Operations. 

Secondary Glaucoma, or that form which arises in conse- 
quence of some pre-existing disease of the eye, may, like the 
primary variety, assume an acute or chronic type. 

It may follow inflammation of the iris and ciliary body with 
the production of extensive synechise ; ulcers of the cornea which 
have perforated and produced considerable anterior synechise or 
staphylomatous bulging ; swelling of the crystalline lens, after 
discission ; dislocation of the lens ; detachment of the retina, asso- 
ciated with severe hemorrhage ; the growth of a choroidal sar- 
coma or other intraocular tumor ; and choroido-retinitis or 
disease of the retinal vessels. 

In most of the instances mentioned there is no difficulty in 
diagnosticating secondary glaucoma by the history of the case, 
and the knowledge of the pre-existing disease. This is not so 
easy if the original trouble has been deep in the eye, like a sar- 
coma. In these cases the type of the disease is usually absolute. 

Treatment. — Secondary glaucoma requires the same treat- 
ment as in the primary form of the disease. A dislocated lens, 
or a lens swollen after discission for cataract, should be re- 
moved. The formation of absolute glaucoma associated with 
great pain, and if there is any suspicion of intraocular growth, 
indicates excision of the globe. 

Hemorrhagic Glaucoma is one type of secondary glaucoma, 
in which numerous retinal hemorrhages appear as the result of 
thrombosis of the retinal vessels, or hyaline degeneration of 
their walls, or from other causes likely to produce extrava- 
sation of blood (albuminuric retinitis). The tension rises and 
the character of the disease may be either acute, subacute, or 
chronic. 

If seen at a time when there are numerous retinal hemorrhages 
and the ordinary ophthalmoscopic appearances of glaucoma, it is 
quite impossible to decide whether the glaucoma is secondary to 
the hemorrhages, or the hemorrhages simply associated with the 
glaucoma. Hemorrhage into the vitreous may occur, obliterating 
the fundus reflex, and then the cornea is steamy, the anterior 



GLAUCOMA. 385 

chamber obliterated, the iris discolored, and the eyeball intensely 
injected and very hard. 

In these cases iridectomy is not usually followed by good re- 
sults. It may lead to permanent blindness by fresh hemorrhagic 
exacerbations. It' attempted it should be preceded by posterior 
sclerotomy. The results of anterior sclerotomy are more favor- 
able than those of simple iridectomy. Tapping the vitreous alone 
may be followed by relief. If the pain becomes intense and 
blindness ensues, enucleation is required. General treatment is 
of importance, as the patients are usually the subjects of general 
vascular disease : ergot, the cautious use of cardiac sedatives, and 
strict regulation of the diet and mode of life. Locally, measures 
to relieve ocular congestion and the myotics may be employed. 

Complicated Glaucoma. — Two kinds of complicated glau- 
coma are described which may be looked upon as varieties of the 
secondary form of the disease, namely, cataract with glaucoma, 
and high myopia with glaucoma. In the former condition one 
eye alone is usually affected. This complication does not refer 
to those eyes which go on to absolute blindness from glaucoma, 
or to contain opaque lenses as the result of a general degene- 
rative process of the eye. 

In high myopia with glaucoma, the usual symptoms in the 
field of vision and the papilla are present. In addition to this 
there is more or less choroidal change, which is itself the cause 
of the glaucomatous attack. 

Hydrophthalmos, or that disease of the eye which has been 
looked upon as a congenital glaucoma, has been described on 
page 294. 

25 



386 DISEASES OF THE EYE. 



CHAPTER XIII. 

DISEASES OF THE CRYSTALLINE LENS. 

Congenital Anomalies. — In addition to congenital cataract 
and congenital displacement of the lens, which are described on 
page 394, two anomalies require mention. 

1. Coloboma of the Lens. — This defect occurs usually with 
a similar defect in the iris and choroid. The normal, rounded 
margin of the lens is replaced by a straight margin in a horizon- 
tal direction, or incurved. The amount of the defect varies from 
a slight indentation to about one-quarter of the lens substance. 
It is always situated in the inferior half of the lens (Heyl). 

2. Lenticonus. — This is an abnormal curvature of the posterior 
surface of the lens, or an anomaly of the nucleus (L. Miiller), 
either unilateral and associated with lenticular opacities, or without 
such association, and then usually bilateral. Anterior lenticonus 
also occurs. With the plane mirror a sharp red disc, surrounded 
by dark shadows, like an oil globule in Avater, may be seen (Knapp), 

Cataract. — Under the term cataract are included several types 
of an opaque condition of the crystalline lens, of its capsule, or 
of both these structures, which anatomically are distinguished by 
the titles lenticular, capsular, and capsido-lenticular. 

Varieties of Cataract. — (a) Primary; and (b) second en/ 
to disorders in other portions of the eye, or (c) symptomatic of 
a general malady, or local injury. 

A cataract is either partial and stationary, or progressive and 
becomes complete, and clinically is classified as senile, subdivided 
into nuclear and cortical ; congenital or juvenile, subdivided into 
complete or partial ; secondary, or complicated ; traumatic ; and 
after-cataract. 

Cataracts are also classified according to their consistence 
as hard, soft, or fluid, and sometimes are designated by their 
color as black, ichite, amber, etc. Although in many instances 



DISEASES OF THE CRYSTALLINE LENS. 387 

the precise division of cataract into special varieties may be un- 
important, the following table, compiled from the classifications 
employed in various standard works, may be useful to the student 
Bfl a rt'xi/iiie of what has gone before : — 

{1. Lenticular. 
2. Capsular. 
3. Capsulo-lenticular. 

1. Senile \ „.; , I general. 
( (6) nuclear J 



Clinically ■ 



Juvenile or congenital <j v ""(.congenital 

I /i\ ~,>_*;„i ( lamellar, or zonular 



( , . . f complete. 

■ (a) complete -j 

1 pyramidal, or polar. 

(anterior polar cataract, 
posterior polar cataract, 
complete cataract. 

4. Traumatic. 

5. After-cataract. 

Symptoms. — The following symptoms are present with more 
or less constancy in cataract, exemplified by the senile form of 
this disease. 

(1) Change in Visual Acuity. — The amount of depreciation of 
sight depends upon the situation and extent of the opacity. In 
incipient cataract the swelling of the lens may increase the re- 
fraction of the eye. The so-called " second sight," or the ability 
of patients of advanced years to dispense with reading glasses, 
in itself is strong presumptive evidence of the existence of cata- 
ract. In like manner the change in the lens may produce an 
astigmatism, or alter one previously existing "according to the 
rule" into one "contrary to the rule," i. e., where the meridian 
of greatest refraction is in a direction contrary to the rule. 

(2) Hyperamiia of the Conjunctiva. — This is caused by the strain 
which the effort to see through a somewhat clouded lens produces. 

(3) Pain and Photophobia. — These symptoms are not promi- 
nent ; but sometimes, owing to the condition of disturbed cho- 
roid which commonly is associated with cataract, patients complain 
of dull aching pain, or other asthenopic symptoms. Tinted glasses 
relieve the photophobia and permit slight dilatation of the pupil, 
which somewhat improves vision if the opacity is central. 

(4) Polyopia and Monocular Diplopia are occasionally the 
result of incipient cataract. 



388 DISEASES OF THE EYE. 

(5) The Anterior Chamber. — This may be normal in depth — 
the usual condition ; shallower than normal — indicating a swollen 
lens ; or abnormally deep — a symptom of small lens. 

(6) The Pupil. — This may be natural in appearance and the 
mobility of the iris entirely normal ; but sometimes the effect of 
exclusion of light, or of a mydriatic, fails to induce a dilatation 
of the pupil. 

We speak of the "color of the pupil," and this varies in cata- 
ract according to the degree of maturity and the hue of the 
opacity. Hence, in the unilluminated pupil, no change is seen in 
its color in incipient cataract; but in a ripe cataract, the pupillary 
space may appear dull, gray, and even white, according to circum- 
stances. In examples of so-called " black cataract" the pupil is 
dark. The mere inspection of the pupil, however, without opti- 
cal aid, is not necessarily a criterion of the condition of the lens, 
which continues to increase in size even with advancing years, 
if it remains clear. (Priestley Smith.) But it becomes firmer, 
straw-colored, and reflects more light. This creates a dull sheen 
in the pupil which may be mistaken for cataract. 

Diagnosis. — From what has been said, it is apparent that the 
absolute diagnosis of cataract depends upon the use of the oph- 
thalmoscopy. Since the introduction of the ophthalmoscope, the 
catoptric test has fallen into disuse, although it may be employed 
to determine the presence of the lens, and in the diagnosis of 
black cataract. 

This test is performed as follows : If, in a dark room, a lighted 
candle be moved before a healthy eye with dilated pupil, three 
images of the flame will be seen ; two erect, formed by reflection 
from the convex cornea and anterior surface of the lens, the 
former producing the bright image and the latter the more dif- 
fuse ; and one inverted, relatively clearer, from the posterior 
surface of the lens. If, now, the lens be opaque, the inverted 
image will be wanting, the deeper erect image also disappearing 
when the opacity involves the capsule, the corneal image being 
then alone visible. 

Before using the ophthalmoscope for the detection of cataract, 
the pupil should be dilated, preferably with homatropine or 
cocaine. The examiner then proceeds in the manner described 



DISEASES OF THE CRYSTALLINE LENS. 389 

on page 104, and will detect in incipient cataract spots or streaks 
of opacity, often radiating from the periphery toward the centre, 
which appear black from the interference with the reflection of 
light from the choroid. In like manner the nucleus may be seen 
to be hazy and the periphery clear, or the sectors of the lens are 
strongly marked. The beginning of cataract is also made evi- 
dent by tlaws in the lens, which have been compared to cracks 
in glass, and are known as "stria? of refraction." If the entire 
lens is opaque, no portion of the pupillary space exhibits any 
red reflex from the fundus, although a lens which appears com- 
pletely cataractous through the undilated pupil, may exhibit 
spots of incomplete opacification in the periphery, recognized by 
the transmitted red glare, when the pupil is dilated. The final 
examination with transmitted light should be made with a 4- 16 
D lens. 

With oblique illumination (page 62), the opacities, if incipient, 
appear as white or gray streaks and dots. 

When a progressive senile cataract is fully matured, its presence 
may often be detected without any special examination, except in 
the instances already mentioned, but it is a matter of the utmost 
importance to ascertain when this full maturity has been reached, 
or, in other words, whether the cataract is " ripe." This is deter- 
mined in the following manner : — 

The patient being placed in proper position, the pupillary 
space is illuminated. If the opacity is complete, the opaque 

lens, covered by its capsule, is level 
with the margin of the pupil, and there 
is no shadow ; if not, the major por- 
tion of the opacity is at a level posterior 
A to the plane of the pupil, or, in other 
M words, a clear or partly clear space 
• * is present between the iris and the 
opaque portion, and a dark semicircle 
Shadow of the iris seen appears upon the opacity at the side 

from the front, appearing- on n i_« i_ j.i i« 1 ± mi • 

that side of the iris which is from which the light comes. This IS 
toward the light, L (Fuchs). the shadow of the iris. (Fig. 126.) 

Shining sectors or the transmission of a 
red glare indicate immaturity, even if the shadow is absent. In 




390 



DISEASES OF THE EYE. 



hypermature cataract the shadow is visible, but the surface of the 
lens is flat. 

Development and Course of Cataract. — In progressive 
senile, or as it is sometimes called, simple cataract, there is a period 
of growth from incipiency to full maturity which varies consider- 
ably, and consumes from one to three years or longer. 

Immature cataract, especially of the cortical variety, may re- 
main unchanged for many years. According to Brailey the indi- 
cations are that senile nuclear cataract is a degenerative change, 
while the cortical variety partakes of the nature of an inflamma- 
tion. This slow progress of cortical senile cataract should be 
remembered, and the discovery of strise in the lens need not 
condemn the patient to rapid deterioration of vision. 

The opacities begin either cquatorially, i. e., at the edge of the 
lens ; or centrally, i. e., at the nucleus. In the former case the 
stria? begin just beneath the capsule and are seen both in the an- 
terior and posterior portions. They gradually radiate toward 
the centre (encroach on the pupil-space), the nucleus becomes 
hazy and sclerosed, the cortical layers become opaque, and finally 
the cataract is complete. 

Fig. 126. 




Cortical cataract. 1. Section of lens; opacities beneath the capsule. 2. Opaci- 
ties seen by transmitted light (ophthalmoscope mirror). 3. Opacities seen by 
reflected light (oblique illumination). (Modified from Xettleship.) 



The participation of the nucleus and the cortex is sometimes 
spoken of as mixed cataract. 

In the second variety the nucleus becomes hazy and the 
surrounding cloudiness always remains the most opaque por- 



DISEASES OF THE CRYSTALLINE LENS. 



391 



tion of the cataract, which gradually spreads to the cortex. 
(Fig. 1:27.) 

According to Schoen, senile cataract invariably begins as equa- 
torial cataract, with fine white dots and streaks, while the nuclear 
Bclerosis never appears without equatorial cataract, being secon- 
dary to it, the association occurring first after the sixtieth year. 

Cataract may also begin as a more or less diffuse clouding, 
or in the form of small dots, scattered through the cortex, or in 
opacities which, with transmitted light, resemble dark flocculent 
precipitates. Under the last circumstances the advance is more 

Fig. 127. 




Nuclear cataract. 1. Section of lens, central position of opacity. 2. Appear- 
ance by transmitted light. 3. Appearance by oblique illumination. (Modified 
from XettleshipJ 

rapid than when stria? are the first manifestation. (Swanzy.) 
Instead of going on to maturity, a nuclear haze or a spear of 
opacity may remain stationary, or at least show no practical 
change for years. 

A cataract having reached maturity may proceed to the stage 
of " over-ripeness" and gradually shrink to a flat disc, or there 
may be liquefaction of the cortical matter and displacement of 
the nucleus, a type which is known as Morgagnian rata met. 
Tremulousness of the iris is -ecu in over-ripe cataracts. Fatty 
changes and calcareous degeneration in the lens and its capsule 
may take place. Cataracts which have been caused by diabetes 
may undergo spontaneous absorption; it seems doubtful if the 
Bame phenomenon ever occurs with ordinary senile cataract, 
although one or two examples have been reported. 



392 DISEASES OF THE EYE. 

The cataract, the development of which has just been de- 
scribed is for the most part "hard," i.e., the nucleus of the lens 
is large. Under the age of thirty-five all cataracts are " soft" 
i. e., the nuclei are small or wanting, just as the lenses in which 
they develop have failed to attain the density which later they 
assume. 

Causes of Cataeact. — (1) Age of Life. — The formation 
of that form of cataract which becomes complete is especially 
frequent after fifty years, but occasionally total cataract without 
apparent constitutional cause is found in adolescents. The very 
beginnings of cataract, according to one observer, are not peculiar 
to old age, but appear between the twentieth and thirtieth years 
as an equatorial cataract. 

(2) Sex. — This appears to have no decided influence, the sexes 
being about equally affected, unless it be in the zonular variety, 
in which the greater liability of females has been recorded. 

(3) Disease. — Sugar has been found in the urine of about one 
per cent, of cataract cases, and the cataractous lenses of patients, 
the subjects of diabetes mellitus, at times contain sugar. An ex- 
amination of the urine should always be made in cataract cases, 
especially when developed in young subjects, and sugar carefully 
sought for. Albumin is present in about 6 per cent, of the cases, 
but the etiological relation of nephritis to cataract has not beeu 
proven. 

Cataract has also been noted in connection with idiopathic 
fevers and allied diseases, with gout, rhachitis, syphilis (Bos), 
atheroma of the carotid (Michel), epilepsy and other convulsive 
seizures, meningitis (Bock), certain cutaneous affections (Mooren, 
Rothmund), and with bronchocele. 

(4) Occupation. — Cataract is especially frequent among glass- 
blowers and is attributed to the effect of the radiated heat and 
excessive perspiration. It is not improbable that investigations 
would show the same liability in puddlers and others exposed to 
intense heat. 

(5) Heredity. — Remarkable examples of the influence of hered- 
ity in the formation of cataract have been published. It has 
been noted that the tendency is more marked in the child-bearing 
period, and that the transmission is through the female line ; 



DISEASES OF THE CRYSTALLINE LENS. 393 

transmission through the male line only, however, lias been 
recorded. 

(6) Toxic Agents. — Cataract has been produced artificially by 
poisoning rabbits with naphthalin (naphthalin cataract). In ad- 
dition to the cataract, there arc changes in the retina and vitreous, 
and also general disturbances. 

During epidemics of ergotism patients are at times affected 
with cataract (raphanic cataract), the appearance having been 
noted almost exclusively in the convulsive type of this tox- 
aemia ; hence it is not certain whether the lenticular opacity 
results from the poisoning by the ergot, or ou account of the 
convulsions. 

(7) Traumatism. — This may produce cataract by a direct in- 
jury to the lens, or in an indirect method, for example, by a con- 
cussion (concussion cataract). 

To this category belong those cataracts which have followed a 
lightning stroke. A number of examples are recorded, both 
double and single, partial and complete. In addition to the 
cataract, optic neuritis, optic atrophy, rupture of the choroid, 
iritis, irido-cyclitis, myosis, mydriasis, and palsy of accommoda- 
tion have been observed. 

(8) Diseases of the Eye. — Cataract may be secondary to nume- 
rous acute and chronic affections of the eye, viz., iritis, irido- 
cyclitis, irido-choroiditis, choroiditis, detachment of the retina, 
glaucoma, and diseases of the cornea, especially sloughing ulcers. 
The frequent coexistence of disturbance of the choroid coat and 
incipient cataract has led to the opinion that while opacity of the 
lens (so-called senile) is a condition commonly seen in advanced 
life, it does not, in all probability, depend upon senile changes, 
but is originated in local pathological states involving the nutri- 
tion of the eye itself (Risley). 

(9) Accommodative Strain. — Investigations show that a large 
majority of cataractous eyes are hypermetropic and astigmatic, 
and that the danger of cataract is said to be increased when the 
astigmatism is against the rule, and remains uncorrected. The 
evident prophylactic measure is the use of proper glasses. 

The etiology of cataract is by no means always clear, and often 
several factors are necessary to explain it ; often no direct cause 



394 DISEASES OF THE EYE. 

can be assigned ; often there are extraocular causes aud the cata- 
ract results from nutritive disturbances. 

The following additional facts in regard to the cliuical varie- 
ties deserve attention : — 

I. Senile Cataract {Simple Cataract, Gray Cataract). — This, 
representing the type of geueral cataract, is nuclear, cortical, or 
mixed in its origin, and is rare before the forty-fifth year. It 
may not appear before the sixtieth year. Its course from inci- 
piency to full maturity has been described. 

The color usually is gray, and the nucleus, which itself does 
not become cataractous, but is hardened, may be recognized by 
its yellowish or brownish hue and its waxy appearance. 

If the nucleus is small and the surrounding cortex uniformly 
white, the cataract is comparatively soft ; if the nucleus is large 
and the color of the cataract distinctly gray, or yellowish or 
brownish, it is hard. 

Instead of a gray or grayish-white color, the cataract may be 
yellow or amber, or the sclerosis of the nucleus extends to the 
cortical substance so that the whole lens is brownish and the 
pupil black (black cataract). Occasionally there is opacity of 
the hyaloid membrane, which Fink calls hyaloid cataract. 

Senile cataract generally is bilateral, one eye being more 
affected than its fellow. Occasionally a ripe cataract occurs 
upon one side only, the other lens being not at all or only 
slightly affected. 

II. Juvenile, or Congenital Cataract, appears in the form of a 
complete or partial opacity of the lens, and is comparatively a 
rare affection. 1 

In the complete form, the lens usually is white or bluish-white 
in color, densely opaque, and soft. The eye may be otherwise 
healthy, or there may be changes in the choroid, retina, optic 
nerve (congenital amblyopia), and sometimes vices of conforma- 
tion, as coloboma, microphthalmos, and hydrophthalmos. Dis- 
turbances of nutrition during iutra-uteriue life, changes in the 
choroid, arrest of development, and heredity, have been invoked 
to explain its existence. 

1 In the tables of De Wecker, among 40,000 cases of various forms of eye dis- 
ease, 30 total congenital cataracts arc enumerated. 



I>I.-EASES OF 1 UK CRYSTALLINE LENS. 



395 



In forms of cataract developed in early life the evidence of 
thr influence of heredity is often strong; more usually this is 
lacking in the congenital types. 

General cataracts in young; people (complete cataract of young 
people), may arise without known cause. These are bluish- 
white, often have a sheen like pearl, and are soft. 

Diabetic cataract is also complete, and may be soft or hard ac- 
cording to the age at which it develops. 

There are several varieties of partial congenital cataract : — 

(a) Zonular, or Lamellar Cataract appears, as its name implies, 
in the form of an opaque layer surrounding the clear centre of 
the lens. Usually it is double, but may be unilateral, and is 
either congenital, or forms in early infancy. The cataract is sta- 
tionary in most instances, but occasionally becomes complete. 

If the centre of the pupil is examined, a reddish point sur- 
rounded by a grayish halo will be observed. When the pupil is 
dilated with atropine and examined with the ophthalmoscopic 
mirror, the central dark zone will be apparent, surrounded by a 
reddish circle, due to the reflection from the fundus passing 
through the peripheral part of the lens, which remains clear. 
A rare type is several zones of opacity separated by zones of 
transparency. Patients with zonular cataract act like myopes. 

Fig. 128. 







Varieties of zonular cataract seen in section (Meyer) . 



The cause of lamellar cataract is not certainly known. In 
the congenital variety it is probably due to some developmental 
defect; in the variety arising in early infancy some fault in 
nutrition has occurred. Most often the subjects are rachitic, 



396 DISEASES OF THE EYE. 

and present the teeth and cranial asymmetry peculiar to this 
affection. A history of convulsions is common, and the dental 
defects, which are present in the form of lines, furrows, or 
terraces running transversely across the incisors or canines, 
are considered by Hutchinson to be due to the mercury which 
in all probability was given for the convulsions which caused 
the cataract. Anatomically, lamellar cataract consists of a nar- 
row zone of degenerative change in the lens fibres, situated 
between the nuclear and cortical areas (Lawford). 

(b) Central Cataract (Central lental cataract) consists of a white 
opacity in the central part of the lens, due probably to faulty de- 
velopment at an early stage of intrauterine existence. Sometimes 
vision is surprisingly good, in one case in the author's practice 

amounting to t: ; at other times it may be poor, and defects of 

development in the eye may be present and nystagmus may 
develop. 

(c) Pyramidal Cataract. — This is also known as anterior cap- 
sular or polar cataract, and consists of a small, pyramidal-shaped 
opacity due to hyperplasia of the capsular epithelium. Mules 
suggests that these cataracts may be cretified remains of the 
pupillary membrane, with or without a lymph cone. 

At the posterior pole of the lens an opacity similar to the one 
described may be found, known as & posterior polar, or pyramidal 
congenital cataract. It is caused by vestigial remains of the 
hyaloid artery at its lenticular attachment. These opacities are 
sometimes separated into those which lie beneath the capsule 
and those which exist upon its surface. 

(d) Punctate Cataract is an unusual form of congenital lenticu- 
lar change in which the opacities present themselves in the form 
of more or less fine points, occupying the centre of the pupillary 
space. The cataract remains stationary for a long time. 

(e) Fusiform Cataract is a rare variety characterized by an 
opaque stripe passing from the anterior to the posterior pole oi 
the lens. It may be combined with zonular cataract. 

III. Complicated, or Secondary Cataract. — This may be com- 
plete and arise in consequence of the various diseases of the eye 
enumerated on page 393. Calcareous changes are often seen in 



DISEASES OF THE CRYSTALLINE LENS. 



397 



Buch cataracts. It may also be incomplete, and then is classified 
in the following varieties: 

(a) Anterior Polar Cataract. — In addition to the congenital 
variety of this opacity there is an acquired type, already de- 
Bcribed on page 222. 

(I») Posterior Polar Cataract, ;i> a congenital variety, has been 
described ; but another form is the more or less star-shaped 
opacity sometimes seen at the posterior pole of the lens in high 
myopia, vitreous disease, disseminated choroiditis, and pigmentary 
degeneration of the retina. It may remain stationary for a long 
time, disturbing vision in proportion to it^ density, or it may 
progress and become complete. 

Fig. 129. 





Posterior polar cataract. 1. Section of lens showing portion of opacity; 2. 
Appearance by transmitted light; and 3, by oblique illumination. (Modified 
from Nettleship.) 

IV. Traumatic Cataract. — This occurs by direct injury to the 
lens by some penetrating substance, which lacerates the capsule 
and then permits the entrance of the aqueous humor. The lens 
Mibstance swells up, becomes opaque, and some of it may escape 
into the anterior chamber. Absorption takes place in about six 
weeks. This course represents the most favorable outcome of 
Buch an accident. In other cases there may be iritis, cyclitis, 
and secondary glaucoma, owing to the swelling of the lens. 

Instead of going on to complete opacity, an injured lens, in 
some instances, presents a limited opacity, which remains sta- 
tionary ; in other instances this disappears, and in still others 
there is slow advance of the opacity. 

The opacity is explained by the action of the sodium chloride 
of the aqueous humor upon the globulin of the lens-substance. 

A more indirect mechanism of traumatic cataract is concussion 



398 DISEASES OF THE EYE. 

(concussion cataract) — a blow upon the eye causing a slight 
rupture of the anterior or posterior capsule, followed bv opa- 
city, which may become general or retain a limited size for a 
long time. According to Nettleship, absorption of a complete 
concussion cataract is more uncommon than when the lenticular 
opacity has followed a direct trauma, although the lens may 
gradually shrink in size. 

V. After-Cataract. — This name has been applied to those 
changes which occur in the capsule of the lens remaining after the 
extraction of cataract. It is usually called secondary cataract. 

These changes are either closure of the opening made in the 
capsule, opacity of the capsule itself from proliferation of its 
cells, or increased thickening in the capsule which may have 
existed before the lens was removed. The name has also been 
given to deposits of lymph, plastic exudate, and occlusion of 
the pupil which have followed unsuccessful cataract operations. 

VI. Capsular Cataract — The name capsular cataract is ap- 
plied to thickenings and proliferations of the capsular epithelium 
which may be congenital, may follow inflammatory processes of 
the eye (corneal ulcer), and may occur in connection with other 
degenerations in over-ripe cataract. 

VII. Capsulo-lenticular Cataract is the name applied to 
opacity of the lens associated with thickening of the surround- 
ing capsule, most commonly in the centre of its anterior portion. 

Prognosis. — Incipient cataract in the form of striae in the ante- 
rior cortex, need not doom the patient to rapid deterioration of 
sight, because the existing vision is often maintained for long 
periods of time. Cataracts, however, do not spontaneously dis- 
appear, except in rare instances. 

Operation is generally deferred until the cataract is " ripe" but 
even then it must be ascertained whether the eye itself is in a 
healthy condition by attention to the following considerations : — 

(a) The Probable Condition of the Inferior of the Eye, if no data 
of ophthalmoscopic examinations during the incipiency of the 
cataract arc at hand. This is ascertained as follows : — 

Place the patient before a lighted candle about four metres 
distant — the flame should be distinctly recognized. This givefl 
evidence that the macular region is free from coar>e disease. Now 



DISEASES OF THE CRYSTALLINE LEN-. 399 

cause the rye under examination to fix the flame attentively; and 
move a second lighted candle radially through the field of vision. 
The Maine should be recognized as soon as the rays strike the 
edge of the cornea, and the patient should be able to indicate 
the direction in which it is coming. Thus the "light field," or 
the "projection of light," is tested, and, if the answers have 
been accurate, " projection of light is good in all parts of the 
field." 

If the patient fails to appreciate the candle flame in any por- 
tion of the field, coarse changes may be suspected, e. g., exten- 
sive choroiditis, detachment of the retina, glaucoma, etc. Fluid 
vitreous, indicated by tremulousness of the iris, is a bad sign. 
Should there be no light-perception, the case is an unsuitable one 
for operation. Even with these precautions, a perfect cataract 
extraction may fail to secure good vision on account of a small 
patch of central choroiditis. 

(b) The Probable Condition of the Refraction. — It may be 
quite impossible to ascertain this unless some record is at hand 
of an examination when the media were still clear. Some idea of 
the refraction is obtainable by examining the glasses which the 
patient may have used during his reading days. High myopia 
renders the prognosis unfavorable ; indeed, the vision after opera- 
tion in myopic cases, other things being equal, is not so good as 
that in hyper metro pes. 

(c) The Mobility of the Iris; its Reaction to a Mydriatic. — This 
should be prompt and normal. Failure of iris reaction in either 
case may indicate imperfect conductive power in the optic nerve, 
or atrophy or other change in the iris. 

(d) The Age and General Condition of the Patient. — Advanced 
age does militate, as much as it would seem likely to do, against 
successful cataract extraction. So, too, the extraction of diabetic 
cataract is often followed by good results ; and even the presence 
of chronic Bright's disease, while a complicating circumstance, 
does not forbid the operation. Great feebleness, dementia likely 
to become worse with confinement, naso-pharyngitis, and chronic ' 
bronchitis are unfavorable conditions. 

(e) Tlie Condition of the Ana of Future Operation and of its 
Surroundings. — Disease of the lachry mo-nasal channels, granular 



400 DISEASES OF THE EYE. 

lids, chronic conjunctivitis, or blepharitis contraindicate cataract 
extraction, because the wound is almost certain to become infected 
by the unhealthy discharges. A fact of importance, not always 
attended to, is the state of the posterior nares. This should be 
reasonably healthy to secure the highest type of success. 

(f) The Type and Condition of the Cataract. — In making a 
prognosis the size of the nucleus and its position, the probable 
consistence of the cortex, the primary or secondary nature of the 
cataract, and its stage of maturity must be considered. Special 
considerations (amblyopia) influence the prognosis in complete 
congenital cataract, and in the partial varieties, like the lamellar 
form, as the eye may be of imperfect construction. In traumatic 
cataract the extent of injury to parts other than the lens must be 
regarded. 

Treatment. — This may be divided into the treatment of im- 
mature and mature cataract. 

Drugs do not exist which can dissolve a growing cataract ; and 
the use of electricity, which has been recommended, is of no 
value. None the less, much comfort can be given to a patient with 
incipient cataract by attending to the following directions : — 

(1) The refraction should be carefully tested and that glass 
ordered which gives the most accurate vision. It may be neces- 
sary to make frequent changes in the correcting lenses, to con- 
form to the alterations in refraction brought about by the 
swelling of the lens. 

(2) The common congestion of the choroid coat is relieved by 
the exhibition of certain alteratives, among which the iodides of 
sodium and potassium are the most suitable. These may be com- 
bined with small doses of bromide of potassium or bromide of 
sodium. Tonic doses of strychnia or tincture of mix vomica 
likewise serve a useful purpose. If by these means the asthenopic 
symptoms are relieved, the moderate use of the eyes may be per- 
mitted without danger of hastening the process of maturation. 

(3) If glasses do not avail, some comfort may be given by 
keeping the pupil dilated with a weak mydriatic (if the opacity 
is central), and thus improving vision. In other cases a myotic 
is useful. 

Artificial Ripening. — The exceeding slowness with which 



DISEASES OF THE CRYSTALLINE LENS. 401 

:t senile cataract may progress often leave- the patient in a stage 
of semi-blindness. To remedy this, several methods have been 
proposed for hastening the process of ripening: 

Simple division oi' the anterior capsule; division combined 
with iridectomy (Mooren); division and external massage (Roh- 
nier); iridectomy and triturating the lens fibres by rubbing the 
cornea over the colobuma with a horn spoon (Forster's method); 
paracentesis <>t the cornea, and internal massage directly on the 
anterior capsule with a small spatula (Sasso and Ricaldi and B. 
Bettinann, of Chicago); and simple paracentesis of the cornea 
with external massage (T. R. Pooley, of New York, and J. A. 
"White, of Richmond, an operation practised by the latter surgeon 
with much success). 

A discission, after the manner of Graefe, carried deep into the 
lens substance, is recommended by some surgeons (Schweigger) 
as the only satisfactory method, especially before the fortieth 
year. 

Extraction of Immature Cataract. — Some operators of 
extensive experience (Schweigger) hold that the usual criteria of 
ripeness are erroneous in that period when accommodation is 
annulled by physiological changes in the lens — that is, about the 
sixtieth year — and the lens may be extracted safely even if it is 
in part unclouded. It may also be done successfully at an earlier 
age. 

Finally, certain operators (McKeown, Wickerkiewicz, Panas, 
Lippincott) perform extraction of immature cataract by the help 
of a syringe with which the tenacious cortical material is washed 
out by the injection of warm distilled water or boric acid solution. 

If the unripe material is not removed it may swell up and 
cause iritis. Therefore the safest plan is to wait for maturity ; 
but, as Knapp says, it is safer to extract an unripe cataract than 
to perform a ripening operation. 

Ma fare cataract requires an operation for its removal, differing 
according to the age of the patient and the consistency of the 
cataract. 

Hard cataracts, or those which occur after the fortieth year, are 
suitably removed by one or other of the following methods: (a) 
The flap method, or simple extraction (extraction without iridec- 

26 



402 DISEASES OF THE EYE. 

tomy) ; (b) the modified or peripheral linear extraction (Von 
Graefe) ; (c) the short or three millimetre flap (De Wecker). 

Soft cataracts, or those which occur before the thirty-fifth year. 
are suitably removed by (a) linear extraction ; (I)) the needle 
operation, or that of solution by discission ; and (c) the suction 
method. A soft cataract before the twenty-fifth year may be 
removed through a linear incision into the cornea, and a semi- 
fluid one by suction. Complete cataract of young; people and 
complete congenital cataract are generally removed by discission, 
the latter variety of cataract being ready for operation after the 
completion of dentition. 

Partial congenital cataracts (central, lental, and lamellar) are 
treated by iridectomy or by discission. The former procedure 
is better if, after dilatation with a mydriatic, there is sufficient 
improvement in vision to justify the manufacture of a new pupil, 
or glasses do not improve vision. This should be made opposite 
to the clearest part of the lens. If this does not prove satisfac- 
tory the lens may be needled, or, finally, the entire lens may be 
extracted. 

Discission is the method of operating applied to after-cataracts. 
Pyramidal, punctate, and fusiform cataracts are not- generally 
amenable to operative treatment. 

Extraction of monocular cataract will not give the patient in- 
creased visual acuity, because, owing to the inequality of refrac- 
tion, the eyes will not work together. The operation may be 
performed (simple extraction) for cosmetic reasons, to avoid over- 
maturity in the opaque lens, and to improve the field of vision 
upon the affected side. If there is divergence, a subsequent ad- 
vancement of the interims may be necessary. 

The technique of performing the various methods of cataract 
extraction, the dangers and accidents, will be described on 
pages 614-635. 

After a successful extraction or solution, and after sufficient 
time has elapsed to secure firm healing, a suitable pair of lenses 
should be adjusted — one for distant vision and one for reading. 

Removal of the crystalline lens produces thecondition techni- 
cally spoken of as aphakia, and causes a high degree of hyperme- 
tropia, in the emmetropic eye corresponding to about 11 I). The 



DISEASES OF THE CRYSTALLINE LENS. l<>. -> , 

degree of hypermetropia will be diminished if the previous 

it tract ion lias been myopic, and it is possible to produce enime- 
tropia, provided the former nearsightedness lias been of such 
degree that the removal of the lens exactly neutralizes it. 

Under ordinary circumstances the correcting lens for distant 
vision is about -4- 10 D. The glass for reading and similar 
occupation should be placed from sixteen to twenty-five centi- 
metres from the eye, according to the usual acuity. In other 
words, a lens having a focal distance of 16—25 cm. is added to 
the distance glass. 

In addition to the hypermetropic refraction which follows cata- 
ract extraction a certain amount of regular astigmatism is the 
result of the operation, due probably to failure of the wound to 
fical properly. This astigmatism is generally "contrary to the 
rule," and is often higher during the first month or two after the 
extraction, or until cicatrization is complete. Usually not more 
than 3 D remains permanently, but even 1 D should be sought out 
and corrected. The astigmatism may diminish during the first 
two or three months after operation. 

( Masses should not be adjusted until all redness has disappeared 
from the eye, and they should not be worn constantly at first. 
It is wise to wait from six weeks to two months before ordering 
the glasses for constant use. 

The amount of vision obtained after a cataract extraction varies 
considerably. Perfect acuity of sight is frequently secured, i. c, 

_(— V but more ofteu patients must be content with lower 
6 \xx/ 

degrees, |, or, according to some operators, T ^ of normal vision 

being considered sufficient to place the case within the category 

of successes. 

Acuitv of vision may usually be considerably raised by 
dividing the capsule of the lens which remaius behind, and 
some surgeons perform this operation almost as the rule. (See 
( Operations.) 

Dislocation of the Crystalline Lens. — This may be con- 
genital (ectopia lentis), and is then due to a relaxation or absence 
of the zonula. The displacement ordinarily is incomplete, aud 



404 



DISEASES OF THE EYE. 



really consists in a decentration of the lens; but complete con- 
genital luxation is also described. Congenital cases are usually 
symmetrical. Several members of the same family may be af- 
fected. Monolateral cases are also described. 

Fig. 130. 




Spontaneous dislocation of lens into the anterior chamber of highly myopic eye. 
(From a patient in the Philadelphia Hospital. Drawing by Dr. Randall.) 



In addition to congenital dislocation there are those due to 
disease of the eye, e. g., choroiditis, malignant myopia, etc., and 

those caused by traumatism. 
FlG - 131 - This dislocation may also be m- 

complete or complete; if the lat- 
ter, the lens may be dislodged 
from its normal position back- 
ward into the vitreous, forward 
into the anterior chamber, or, 
through a wound, beneath the 
conjunctiva, and even under 
Tenon's capsule. 

Sym ptoms. — If the disloca- 
tion is partial, the margin of the 
lens may be seen as a dark line 
with the ophthalmoscope, the 
refraction of the eye will vary according to the point through 




Subconjunctival dislocation of the 
lens. (From a patient in the Chester 

County Hospital.) 



DISEASES OF THE CRYSTALLINE LENS. !<>."> 

which it i- observed (i. '..through the Ions or beyond it), the iris 
is tremulous from loosening of the suspensory ligament and lack 
of the support of the lens, and monocular diplopia and impaired 
or absent power of accommodation are demonstrable. If there 
is complete posterior luxation the symptoms are much the same 
as when the lens has been removed by operation, and if the cause 
of the dislocation is trauma, the symptoms of the injury, e. (/., 
hemorrhage, etc., may be present. 

A dislocated lens usually becomes cataractous, and often causes 
intense pain and frequent attacks of iritis, or by occluding the 
angle of the anterior chamber may give rise to glaucoma. 

Treatment. — In partial dislocation an attempt should be 
made to secure the best vision with suitable glasses. 

In complete luxation into the anterior chamber the lens may 
be removed by a simple corneal incision. For removal of a 
lens dislocated into the vitreous humor, provided it is producing 
irritation, a scoop introduced through a peripheral corneal in- 
cision may be employed, or the operation devised by the late C. R. 
Agnew may be attempted. In the latter, a double needle or 
"bident" is thrust into the vitreous humor far enough back- 
to avoid wounding the iris, the handle of the instrument is 
depressed, the lens is caught and brought forward through the 
pupil into the anterior chamber, and removed in the ordinary 
way. Knapp prefers, under these circumstances, after thorough 
local anaesthesia, to expel the lens by methodical external press- 
ure, through an upper corneal section, after removal of the spec- 
ulum. He presses the edge of the under lid on the lower part 
of the sclera, directly toward the centre of the eyeball. If this 
fails, he introduces a wire or metal spoon through the corneal 
section and the pupil, and extracts the lens in this way. 

If the lens has been dislocated beneath the conjunctiva, it 
should be extracted through a small incision made directly over it. 

After the successful removal of a dislocated lens the eye should 
be provided with cataract-glasses. 

Foreign Bodies in the Lens. — Foreign bodies lodged in 
the lens usually cause general opacity. Occasionally the body 
is surrounded by a small opacity which remains localized. If a 



406 DISEASES OF THE EYE. 

piece of steel or iron is imbedded in the superficial layers, it may- 
be dislodged with the electro-magnet, and. even from the deeper 
layers by the powerful magnet of Haab. If the lens is opaque, 
the whole crystalline lens, with the foreign body in it, should be 
extracted, lest the foreign body become displaced and disappear 
within the eye. 



DISEASES OF I UK VITREOUS. 4U7 



CHAPTER XIV. 

DISEASES OF THE VITREOUS. 

Hyalitis. — Under the general term hyalitis, provided this is 
understood to refer to the vitreous humor and not to its sheath 
(the hyaloid), may be included the two types of inflammation of 
this body — the one connected with suppuration, and the other with 
the formation of opacities. Under almost all circumstances the 
hyalitis arises in consequence of diseases of the uveal tract, retina, 
optic nerve, or from injury. 

Purulent Inflammation of the Vitreous {Suppurative Hya- 
litis). — This condition is caused by a penetrating injury, a 
foreign body, and arises in connection with purulent choroiditis ; 
for instance, as the product of a metastatic choroiditis after in- 
flammation of the cord in newly-born children, or after scarlet 
fever, erysipelas, relapsing fever, etc. 

There is also a good deal of evidence to show that there may 
be a spontaneous infUmvmation of the vitreous which may mani- 
fest itself simply by opacity, or go on to suppuration. Pus in 
the vitreous may be due to exhaustion and debility consequent 
upon low fevers, or, in general, the infectious blood diseases. 
Suppurative hyalitis may start from operation scars from a few 
months to seven years after healing. The inflammation is of 
microbic origin. 

Symptoms. — If the cornea is clear, a yellowish reflex is seen 
shining through the pupillary space, there is retraction of the 
periphery of the iris, and bulging of its pupillary border. Usually, 
one or two synechia are present, and the tension is diminished. 
In addition to this there may be a pericorneal zone of congestion 
connected with the inflammation of the iris and ciliary body. 

When the pus in the vitreous is circumscribed, the symptoms 
at the first glance are not unlike those of glioma of the retina, 
and the name pseudo-glioma ha- been given to this condition, 



408 DISEASES OF THE EYE. 

especially as it is seen in children. It is, however, to be distin- 
guished from a true glioma of the retina by the history of the 
case, the usual presence of the signs of iritis, the retraction of the 
periphery and bulging of the pupillary border of the iris, and the 
diminished tension of the globe. 

Treatment. — If pus has once formed in the vitreous, in the 
manner just described, no medicinal treatment is of avail; the 
ball will go on to shrinking, and enucleation is usually necessary. 
Intraocular injections of chlorine water have been recommended. 

If, during the earlier stages of this affection — for instance, 
during the course of a low fever — the discovery is made that 
fine flakes of opacity are beginning to appear in the vitreous, it 
is possible that a vigorous supporting treatment may save the 
eye from destruction. (Hansell.) The possibility of the occur- 
rence of such a condition during low fevers should lead the 
physician to frequent investigation of the eyes. 

The second type of inflammation of the vitreous is that which 
is attended with the formation of opacities, and hence may be 
described under the most prominent symptom of the disorder: — 

Opacities in the Vitreous. — These are either fixed or moving, 
and vary considerably in shape, size, and somewhat in color. 
The opacities may appear in the form of membranes, bands, dot-, 
threads, flakes, and strings ; or, finally, the entire vitreous humor 
may give evidence of uniform loss of translucency, which on 
careful focusing resolves itself into a diffuse, dust-like opacity. 

The fixed membranous opacities are usually adherent by two 
or more points to the choroid, retina, optic disc, and sometimes 
to the ciliary processes, and even to the posterior capsule of the 
lens. They may exist as a membrane which crosses the vit- 
reous and covers the optic disc, or as membranous bauds run- 
ning from before backwards, and may be coarse, dense, and or- 
ganized, or fine and more like a cobweb in texture. 

Method of Detection. — The examination of the vitreous is made 
after the manner described on page 105. 

The rapidity with which the bodies move depends upon the 
consistency of the vitreous humor; if this is natural, the move- 
ment is slow; if it is fluid or semi-fluid, the movement is corre- 
spondingly rapid. The excursion made by opacities in the vit- 



DISEASES OF I'll I' VITREOUS. 409 

reous bumor has been compared by Mr. Nettleship to the move- 
ment of solid particles and films in a bottle filled with liquid 
after the bottle has been shaken. 

Vitreous opacities move in the direction opposite to that which 
the eye takes — that is, if the eye is turned upward, the opacity 
moves downward — while an opacity on the cornea, or in the lens, 
moves with the movements of the eye. Moreover, an opacity <>\ 
the vitrei uis docs not at once come to rest when the eye stops 
moving, but slowly settles ; while one situated upon the cornea 
or the lens ceases its movement as soon as the eye stops. (Com- 
pare with page 105.) Finally, any opacity upon the cornea, or 
even upon the lens, can be excluded by the use of oblique illumi- 
nation (page 62). 

The different layers of the vitreous may be examined for fixed 
opacities by means of the upright image in the ordinary way, by 
first finding the optic papilla, then gradually placing stronger 
and stronger convex lenses behind the sight-hole of the mirror 
until a + 16 D is in place, thus bringing everything into 
focus from behind forward. The observer's head must be close 
to the observed eye. In the same way Knapp has proposed to 
make use of the inverted image, gradually removing the convex 
lens from the eye and bringing into view the parts from behind 
forward until those which are anteriorly situated are in focus. 

The subjective symptoms of vitreous opacity depend entirely 
upon their amount and density. There may be little or no depre- 
ciation of central vision, or this may be cut down and even en- 
tirely obliterated. Patients frequently complain of black and 
gray spots before their eyes; sometimes these assume fantastic 
shapes, and not infrequently these shapes repeat themselves so 
constantly that the patient is able accurately to describe them or 
even to draw them. The same symptoms may appear where there 
is no organic disease (page 412). Changes in the field of vision, 
pain, redness of the eye, or similar conditions will depend largely 
upon associated changes, and usually are absent if the vitreous 
alone is affected. 

CAUSES. — (1) Refractive Error, probably almost exclusively 
high di'^i'M-s of myopia associated with changes in the choroid 
and the formation of a posterior staphyloma. 



410 DISEASES OF THE EYE. 

(2) Diseases of the Eye, chiefly cyclitis, iridocyclitis, choroid- 
itis and retinitis. 

The shape and character of the opacities vary with the condi- 
tion which has caused them. In cyclitis and irido-cyclitis 
inflammatory opacities are seen ; in chronic and old-standing 
choroiditis flake-like or thread-like opacities are very common, 
especially in elderly people, and are probably due to hemorrhages 
having their origin in the choroid. In syphilitic choroiditis and 
retinitis, in addition to large, floating opacities, there may be 
a diffuse mist which resolves itself into the so-called dud-like 
opacities (hyalitis punctata), and is almost characteristic of the 
disease which has caused the original inflammation of the choroid 
and retina. The situation of these dust-like opacities is either 
diffuse through the entire vitreous chamber, or in its posterior 
layers, or anteriorly, in the neighborhood of the ciliary region. 

(3) Injuries of the Eye, which have caused a hemorrhage from 
the choroid or ciliary region. The origin of the opacity is an 
extravasation of blood. In the latter case, as has already been 
mentioned, suppuration of the vitreous is likely to occur. 

(4) Diseased Conditions of the System, Local or General. — Ex- 
haustion of infectious blood diseases or low fevers, wide-spread 
endarteritis, gout, syphilis, malaria, portal congestion, constipa- 
tion, anaemia, and irregular or suppressed menstruation cause 
vitreous opacities ; also the prolonged action of arsenic. 

(5) Absence of Apparent Cause. — Opacities of various shapes, 
often fine and thread-like, and commonly seen in old people, 
occur without evident disease of the uveal tract, retina, or optic 
nerve. Their presence in some instances is without serious im- 
port. Sometimes the vitreous is studded with minute light-col- 
ored spheres ; probably a congenital condition, named asteroid 
hyalitis by Benson. 

It will be seen from what has been said that the origin of 
vitreous opacities is from various morbid processes, and they may 
represent the result of an inflammation, a hemorrhage, or a de- 
generation of the vitreous cells or its constituent parts ; that in most 
instances the opacities are secondary to changes in other portions 
of the eye ; but that, both with and without suppuration, a pri- 
mary inflammation may start in the vitreous body itself. 



DISEASES OF THE VITREOUS. 411 

Prognosis, — This depends entirely upon the cause of the 
vitreous disease. If this has started in a purulent disease of the 
choroid, or a purulent change in the vitreous has taken place, the 
prognosis is exceedingly bad and the eye goes on to destruction. 

If the cause of the disease is syphilis or other constitutional 
condition amenable to treatment, satisfactory clearing of the 
vitreous may be expected ; even very dense opacities will disap- 
pear under proper treatment. When the opacities are due to 
hemorrhage the absorption of the clot is not so likely to take 
place. Both hemorrhagic opacities and others are subject to re- 
lapses. 

Treatment. — In any ease of vitreous opacity, provided the 
general fundus of the eye-ground justifies this, and there is reason 
to believe that eye-strain in any sense is connected with its cause, 
suitable lenses should be ordered, but the use of the eyes at close 
ranges should be discouraged. 

In syphilitic vitreous disease the usual remedies are applicable. 
When the vitreous change depends upon an exhausted condition 
of the system supportive measures are indicated. 

If the patient is in condition to receive this, excellent results 
follow sweats with pilocarpine or jaborandi. The drug may 
also be used in small doses not sufficient to produce sweating, 
and seems to have an alterative effect. 

If vitreous disease depends upon constipation and portal con- 
gestion, in addition to a regulated diet, cholagogue laxatives 
should be administered. Anaemia and menstrual irregularities 
are evident indications for treatment ; in the former case the 
combination of bichloride of mercury with iron is useful. If 
there is an active inflammatory condition, local blood-letting from 
the temple should be practised ; in fact, the treatment then be- 
comes that of the acute inflammation which has started the dis- 
order. The use of the galvanic current has been warmly recom- 
mended by some surgeons in vitreous opacities. 

A dense membranous opacity, more or less fixed and general, 
may be subjected to a needle operation. According to Bull, an 
ordinary discission needle should be inserted in front of the 
equator of the eyeball and just below the lower border of the 
external rectus muscle, and the membrane divided. 



412 DISEASES OF THE EYE. 

Muscae Volitantes (Myodesopsia) are the black specks and 
motes often seen floating in the field of vision, especially if the 
eye is directed towards a bright surface. They follow the move- 
ments of the eye, and are especially annoying during the act of 
rending, as they float across the page. They do not interfere 
with vision. 

There is no true opacity of the vitreous, and the ophthalmo- 
scope fails to detect in these instances any floating opaque par- 
ticles. They are probably due to the shadows thrown upon the 
retina by naturally-formed elements in the vitreous bodies, per- 
haps the remains of embryonic tissue. 

Although of no serious import, so far as sight is concerned, they 
produce an amazing amount of annoyance in nervous and sen- 
sitive patients. Patients frequently complain that they obscure 
an object, floating directly in front of it, and assume exaggerated 
and fantastic shapes. They are often ascribed by the laity to dis- 
orders of digestion and torpidity of the liver, and are aggravated 
by the habit which their possessors form of searching for them. 

Treatment. — Any cause of eye-strain should be removed, 
and a course of alterative tonics may be ordered. In short, in 
troublesome cases, the treatment is much the same as would be 
applied to an ordinary instance of asthenopia. 

Hemorrhage into the Vitreous. — As has already been stated, 
many vitreous opacities result from hemorrhages from the ves- 
sels of the choroid, ciliary body or retina. Injury is a common 
cause of hemorrhage in the vitreous, and under such circum- 
stances the entire chamber may be so filled with blood that it is 
easily detected in its natural color as a dark red clot, sometimes 
being so dense that no reflex comes from the fundus. 

Finally, in certain cases, generally in young male adults, spon- 
taneous hemorrhage into the vitreous occurs, together with hem- 
orrhage in the retina. According to Eales such patients are 
liable to constipation, irregularity of the circulation and epis- 
taxis. Hutchinson thinks that gout may be a cause in some 
cases. There is marked disturbance of vision depending on the 
density of the clot, which is likely to be imperfectly absorbed. 

Treatment. — This consists in local depletion, cardiac seda- 
tives, ergot, laxatives, and later the administration of small di 



DISEASES OF THE VITREOUS. 413 

(if iodide of potash. As in other vitreous changes, if the general 
condition permits it, a sweat-cure may be tried, either by means 
ot' the Turkish bath or with jaborandi. 

Synchisis (Fluidity of the Vitreous). — This is a softened or 
fluid condition of the vitreous, which, as has already been im- 
plied, can be positively diagnosticated, or, rather, assumed to be 
present, only by noticing the rapid movement of particles of 
opacity contained within it during motions of the eye. Although 
tremulousness of the iris is sometimes seen when there is decided 
fluidity of the vitreous humor, this symptom does not prove its 
condition, but only a lack of support by the crystalline lens owing 
to relaxation of the zonula. The tension of the eyeball may be 
diminished. 

It occurs in elderly people with disease of the choroid coat, 
and with staphyloma. A fluid vitreous may be a complicating 
circumstance in an eye in which an operation is performed; for 
instance, in a cataract extraction, sometimes causing excessive 
loss of the vitreous after the corneal incision. 

Synchisis Scintillans is a term applied to a fluid vitreous 
which holds in suspension numerous scales of cholesterin w T hich 
move with great rapidity across the ophthalmoscopic field and pro- 
duce a striking picture, resembling a shower of brilliant crystals. 
Poncet has reported in this connection tyrosin and crystallized 
phosphates, but recent investigations seem to show that the ap- 
pearance is due solely to cholesterin. 

The affection probably depends upon a choroiditis, and is said 
to be more common among alcoholic subjects and those with 
arthritic tendency or any serious disorder of nutrition. The 
affection is, however, clinically at least, seen in eyes which appa- 
rently are not diseased in other portions, especially in old people, 
and may be present in advanced degree without depreciation of 
visual acuity. 

Treatment. — This does not appear to have any influence. 
Succinate of iron has been recommended. The condition is a 
distinct contraindication to operative measures upon the eye. 

Bloodvessel-Formation in Vitreous. — Occasionally cases are 
examined which present an entire new bloodvessel formation in 
the vitreous in front of the entrance of the optic nerve. (Fig. 132.) 



414 



DISEASES OF THE EYE. 



Fig. 132. 




Bloodvessels in the vitreous flTirsehberg). 

Only a few vessels may be present, or, in extreme cases, the entire 
disc is obscured by a congeries of contorted vessels, the whole 
forming an extensive vascular veil of anastomosing capillaries 
coming directly from the nerve head and having no connection 
with the retinal vessels (Harlan). The vessels have been supposed 
to owe their origin to vitreous hemorrhages ; in other cases the 
origin probably is of a specific nature (Hirschberg). 

Foreign Bodies in the Vitreous — These are usually chips of 
steel, splinters of glass, or small shot. They may reach the 
vitreous by penetrating the sclera directly, or by passing through 
the cornea and lens. The foreign body, if unremoved, may cause 
suppurative hyalitis in the injured eye, or sympathetic ophthal- 
mitis in the fellow eye. The symptoms, diagnosis, and treatment 
of foreign bodies in the vitreous have been included with injuries 
of the sclera, on page 305. 

Entozoa in the Vitreous. — Oysticerci in the vitreous are ex- 
ceedingly rare, except in Northern Germany. 

Another parasite which has been described in the vitreous, at 
least one instance of its removal being on record, is the JUaria 
sanguinis hominis. 



DISEASES OF THE VITREOUS. 415 

Detachment of the Vitreous is a condition which, of itself, 
would uol create blindness; but because it produces detachment 
of the retina, it is a change of the gravest import. 

Traumatism, choroiditis, hemorrhages, intraocular growths, 
and staphyloma may cause it. The vitreous humor is said to be 
occasionally detached without change in its translucency, although 
opacities are usually present. Shrinking of the vitreous after a 
blow on the eve causes its hyaloid to be detached from the retina. 
In eves removed after injury, stretching across the globe behind 
the lens, the so-called cyclitie membrane may be seen. 

Persistent Hyaloid Artery. — During foetal life the vitreous 
humor is traversed by the hyaloid artery, which is an extension 
of the central artery of the retina, and proceeds from the optic 
mrvc to the posterior surface of the lens. The vessel passes 
through a channel, having a delicate membranous lining, known 
as the canal of Cloquet. Obliteration of this artery begins at the 
end of the fifth month of gestation. 

Sometimes obliteration fails, and the most important congenital 
am >maly of the vitreous is evident, namely, the persistence of some 
vestige of the hyaloid artery. It may appear in the following 
forms : — 

A rudimentary strand attached to the disc; a strand attached 
to the disc and a vestige also at the posterior surface of the lens; 
a strand passing from the disc to the lens ; a similar strand con- 
taining blood ; a strand attached to the lens alone ; and a per- 
sistent canal (canal of Cloquet) without any remnant of the vessel. 
These are the most ordinary and well -recognized forms. 

In addition to this, shreds of tissue and membranes on the 
optic disc, masses resembling connective tissue, and small cystic 
bodies are probably remnants of this artery. Its role in pro- 
ducing posterior capsular cataract has already been described. 
The appearances are readily recognized by the ophthalmoscope, 
and require no further description than the names already given. 

This classification has been condensed from the monograph of 
Dr. De Beck, who has written the most complete account of the 
anomaly. 



416 DISEASES OF THE EYE. 



CHAPTER XV. 

DISEASES OF THE RETINA. 

Hypersemia of the Retina. — This condition, independent of 
a true inflammation, is not readily demonstrable with the ophthal- 
moscope. 

Although the capillary network of the retina, invisible under 
ordinary circumstances, may, under other conditions, become 
evident {capillary congestion), the presence of a congestion is 
inferred, not by any alteration in the appearance of the retina 
itself, but by changes in the surface of the optic disc, generally 
known by the terms " increased redness" or " undue capilla- 
rity, " and is associated with increase in the amount of the retinal 
striation which surrounds the papilla, so that its edges are veiled 
or slightly blurred. Such appearances are common in asthm- 
opic and ametropic eyes, and in people whose occupations expose 
them to the glare of artificial heat, e. g., puddlers. 

It is possible to speak with more confidence of a change in the 
calibre, course, color, and general size of the retinal vessels, or, 
in other words, of a hypersemia of the central system. Under 
these circumstances more than the normal amount of blood finds 
its way into these vessels, which consequently are distended, 
tortuous, or positively lengthened. Gowers divides hypersemia 
into an active type, when the increased amount of blood is sent 
to the retina because the systemic circulation is unduly filled, e. g. t 
in rapid action of the heart with fever, pneumonia, etc. ; and a pas- 
sive type, when there is failure of the blood to be returned from 
the eye, for example, in compression of the retinal vein. Then 
the veins are large, filled with dark blood, and often tortuous, 
while the arteries are unaffected, or are smaller than usual. 

Among the general causes of a stasis hypersemia may be men- 
tioned mitral disease, emphysema, violent cough, convulsive 
seizures, or, in short, any cause which is likely to produce engorge- 



DISEASES OF THE RETINA. 417 

ment of the veins of the head and neck, and to prevent the empty- 
ing of their contents into the great venous channels of* the chest. 
Increase in the diameter of the veins is much more frequent than 
increase in the diameter of the arteries, while, on the other hand, 
increase in the diameter of the arteries is uncommon as compared 
with a diminution of their calibre. (Luring.) Pathological signifi- 
cance must not be ascribed to apparent changes in the diameter 
of the veins, because eye-grounds are often crossed by large dark 
veins, the arteries being small by contrast, without definite, local 
or general cause for the phenomenon. 

Ordinarily patients with hypersemia of the retina do not com- 
plain of characteristic symptoms, but when this condition is con- 
nected with ametropia there are ocular pain, photophobia and 
lack of eye-endurance. 

Treatment. — In hypersemia dependent upon refractive asthe- 
nopia, the evident treatment is physiological rest under the influ- 
ence of atropine, and later a suitable correction with glasses. If 
severe, blood may be abstracted from the temples, or dry cupping 
may be employed, and internally, bromide of lithium or sodium, 
with or without ergot, acts well. When the condition depends 
upon general causes, these furnish the indications for treatment. 

Anaemia of the Retina should be looked upon not as a disorder 
of this structure, but as a symptom of local pressure, or of some 
cause situated within the general economy. 

The highest type of anaemia of the retinal vessels is seen with 
stoppage of the circulation by an embolus, and occurs in marked 
degree as the result of compression, in consecutive atrophy of the 
optic nerve. Other causes of ansemia of the retina are general 
amernia, cerebral ameniia, and syncope. 

Extreme narrowing of the retinal arteries is occasionally seen 
as the result of a vaso-motor spasm ; for example in "sick head- 
aches," and in true migraine. In these cases there may be tem- 
porary complete or partial (hemianopic) blindness. If the blind- 
ness approaches from above downwards the obstruction is in the 
retinal circulation, but if it assumes a lateral form, the cortical 
visual centres are probably affected. (Priestley Smith.) Impeded 
retinal circulation may be attributed to the high arterial tension 
which is known to be present in sonic cases of migraine. 
• 27 



418 DISEASES OF THE EYE. 

Under the name ischcemia of tin retince a condition is described 
in which, with complete blindness, there is pallor of the optic discs 
and extreme narrowing of the retinal bloodvessels. This has 
been seen in the collapse-stage of cholera (Graefc), in whooping- 
cough (Knapp, Noyes), in erysipelas (Ayres), and under the in- 
fluence of toxic doses of quinine. 

Treatment. — The flagging circulation should be stimulated 
by digitalis and strychnia. Nitrite of amyl has been employed 
in spasm of the retinal arteries. General anaemia calls for its 
appropriate remedies. 

Hyperaesthesia of the Retina. — This is characterized chiefly 
by the symptoms which indicate a supersensitive state of the 
retina — dread of light, lachrymation, blepharospasm, neuralgic 
pain and imperfect eye-endurance. 

Ophthalmoscopic changes may be practically absent, but in 
most instances those lesions will be detected which have been 
referred to under congestion, but which, adopting a name origi- 
nally employed by Jaeger and used by Loring, may be described 
as irritation of the retina. These are : undue redness of the 
nerve-head, veiling of its nasal edges, from which, and from 
those above and below, distinct striation of the retinal fibres 
are evident, while streaks of light tissue can be followed along 
the course of the larger vessels. The margins of the disc are 
veiled by this retinal striation, and although the physiological 
cup, if present, or the "light spot," may be unchanged, the 
general surface of the disc seems to be covered by a delicate 
layer of cedematous tissue. At the same time the choroid 
reveals changes similar to those described on page 344, or else is 
distinctly granular and macerated. Often the entire fundus fails 
to present a distinct ophthalmoscopic picture, and may be de- 
scribed by saying that the details of the eye-ground are not 
sharply seen by the aid of any correcting glass. 

Causes. — Hyperesthesia and irritation of the retina are usually 
caused by errors of refraction and anomalies of muscle-balance, 
especially in neurasthenic and hysteric subjects. They are also 
seen with chronic headache, neuralgia, and after prolonged fevers 
and pulmonary disorders. In a series of cases which the author 
has reported, oxaluria appeared to be the source of the trouble. 



DISEASES OF THE RETINA. 419 

In some instances of retinal irritation the cause seems to be 
dependent upon changes in the naso-pharynx ; for example, 
engorgement of the septum, associated with myxomatous and 
hypersensitive spots, vaso-paretic and infiltrated turbinals, and 
secondary changes in the pharynx and larynx. Just as areas of 
hyperesthesia in these regions may be part of a general neurosis, 
so, also, they may be both directly and indirectly connected with 
a hyperaesthetic condition of the retina, and the eyes will not 
grow comfortable until the nasal disease is cured. It is probable 
that retinal irritation may sometimes be the forerunner of organic 
change in the optic nerve. (Loring.) 

Treatment. — Spectacles are not a panacea, and although even 
slight errors of refraction should be neutralized, the correcting 
lenses alone do not suffice to relieve the symptoms. General 
tonics, rest, massage, and all measures calculated to overcome 
debility or existing neurosis are required. Although strychnia 
is usually indicated by the general conditions, it may aggravate 
an irritable retina precisely as it does irritations of nervous tissue 
elsewhere. The naso-pharynx should be explored. The urine 
should always be examined, especially with reference to uric acid 
and oxalate of lime. 

Anaesthesia of the Retina (Neurasthenic Asthenopia), like seve- 
ral other disorders of the retina, just considered, should be 
regarded not as an affection peculiar to the eye, but as one of 
the symptoms of a very complicated neurosis. Very often the 
condition described in the preceding paragraph and the present 
affection are closely allied, and with neurasthenic asthenopia there 
may be marked hyperesthesia and irritation of the retina. On 
the other hand such appearances may be entirely absent. 

The subjective symptoms of this condition have been arranged 
by Wilbrand as follows : Peculiar contraction of the field of 
vision ; rapid disappearance from view of any object which is 
being fixed; diminution of central vision; sudden attacks of 
obscuration of vision and processions of scotomas ; visual halluci- 
nations ; lack of fixation of the optical memory-images ; inability 
to read for any length of time ; weariness on the part of the 
muscles both of the eyes and the eyelids ; and positive insuffi- 
ciency of the internal recti. In addition to this there may be 



420 DISEASES OF THE EYE. 

defective accommodation, intolerance of light, and improvement 
of vision in the dusk or through tinted glasses. 

The most characteristic symptom of the affection is a peculiar 
contraction of the field of vision, which at the beginning of the 
examination may present normal limits, but as the examiner 
proceeds, contracts most markedly both above and below the 
horizontal meridian, because the nervous apparatus becomes 
fatigued. If the patient is allowed to rest, and the examination 
is repeated, but the test-object is now moved along the meridians 
in the opposite direction from that in which it was moved in 
the first examination, a second field will be obtained, which is 
called by Wilbrand the counter-field. The most contracted part 
of this counter-field lies on the same side as the most expanded 
part of the previous visual field. The visual field for colors 
exhibits about the same conditions as that for white. This is 
not only characteristic of retinal anaesthesia, but of the retinal 
exhaustion which is found in a variety of conditions. 

Patients affected with this condition are for the most part 
women, often the subjects of ovarian and uterine disease, hysteria 
and chlorosis. It is not an uncommon affection about the time 
of puberty. Although by far the most of its subjects are found 
in the feminine sex, pure types are also seen in men. 

In addition to the local symptoms described in connection with 
the visual organ, these patients have a host of general disturbances 
indicative of their defective nutrition and nervous tone. In 
short, they complain of that series of symptoms which has been 
classified under the much-abused term neurasthenia, or increased 
excitability of the nervous system, with a tendency to rapid 
fatigue. 

Treatment. — This is directed largely towards the general 
condition, and includes in the most advanced types all that is 
meant by the term "rest-cure," namely, rest with seclusion, forced 
feeding, massage, and electricity. Tonics of various kinds are 
indicated, and ascending doses of mix vomica and strychnia are 
especially valuable, provided the retinas are not distinctly con- 
gested. Under proper circumstances, other cases are suitably 
treated by graduated exercise. 



DISEASES OF THE RETINA. 421 

Although tinted glasses are recommended, they are Dot always 
advisable lest the affected eves becomes too much accustomed 
to the dull light afforded through such protection. Any error 

of retract ion should be corrected, but spectacles of all types, and 
all treatment directed towards the ocular muscles, are not alone 
sufficient to cure these eases — cases, moreover, which are con- 
stantly subject to a relapse of their symptoms. 

Retinitis. — Under the general term retinitis are included the 
various types of inflammation of the retina. 

Varieties. — Retinitis may be primary, owing to constitu- 
tional causes and altered states of the blood and bloodvessels ; or 
secondary, owing to extension from an inflamed iris, ciliary body, 
or choroid. It is further divided, according to its character, into 
rim i inscribed and diffuse retinitis ; according to its pathological 
nature, into serous and parenchymatous retinitis; and according 
to its supposed etiology, into the various clinical types presently 
to be described. 

Symptoms. — Certain objective and subjective symptoms are 
present in most of the forms of retinitis. 

(1) Loss in the Transparency of the Retina. — This is the only 
characteristic ophthalmoscopic symptom of retinitis. It may be 
a faint diffuse haze, a circumscribed opacity and swelling, or 
streaks of white infiltration, especially along the lines of the 
larger vessels. 

(2) Areas of Exudation. — These are an advanced process of the 
condition just described. They appear as white spots, sometimes 
discrete, sometimes confluent, or as patches of bluish-gray, buff, 
or yellowish color. They should be differentiated from the 
shining, white plaques due to atrophy of the choroid by their 
softer tone, their situation, and because there is an absence of 
accumulation of choroidal pigment. They may be present any- 
where in the retina, or localized in the macular region. 

(3) Tortuosity of the Vessels and Change in their Calibre. — 
The veins are darker than normal, unduly wavy in outline, 
or positively lengthened in their course. The arteries may 
not be materially changed, but the finer transverse branches are 
often very tortuous, and both sets of vessels are liable to dis- 



422 DISEASES OF THE EYE. 

placement from their normal level as they cross areas of thicken- 
ing, or to partial obscuration by the puffy and infiltrated retina. 
Many vessels invisible in health become injected in retinitis, and 
form a fine red striation, passing from the nerve-head. Pulsation 
of the vessels is readily induced by pressure. 

(4) Hemorrhages. — These occur either in the fibre-layer or the 
deeper portions of the retina. The presence of retinal hemor- 
rhage alone, however, does not indicate the existence of inflam- 
mation, as it may occur quite independently of retinitis. 

When the hemorrhage is placed in the superficial or nerve- 
fibre layer, it usually assumes a flame-shape, with frayed or 
feathery edges; when its situation is in the deeper layer, it has 
a cleaner-cut border and more rounded shape. 

(5) Changes in the Nerve-head. — More or less change in the 
optic papilla is present : undue redness, loss of the distinctness 
of its margins, obscuration by the swollen and puffy retinal 
fibres, or finally positive inflammation or neuritis. Atrophy of 
the disc is commonly present after severe retinitis. 

(6) Pigmentation. — Black spots of pigment mark the situation 
of former retinal hemorrhages. Pigment in the retina, like 
hemorrhages, although in many instances a sequence of retinitis, 
is of itself not necessarily a symptom of inflammation of this 
membrane. 

The difference between pigment in the retina and in the cho- 
roid has been described on page 346. 

(7) Atrophy of the Retina. — This, like atrophy of the choroid, 
may indicate a former hemorrhage, or an area of inflammation. 
All of the retinal layers, as well as the choroid, may be involved, 
exposing a white patch of sclera (atrophic choroido^retinitis), or 
only the superficial layers may be affected, and the spot may be 
marked by a permanent whitish or yellowish opacity. Contrac- 
tion of the vessels and white tissue along their coats are often 
seen after retinitis. 

In addition to the ophthalmoscopic signs there are : — 
(1) Change in Visual Acuity. — Central vision is <liinini--<//><l in 
direct proportion to the severity of the case and the situation of 
the inflammatory action. In the early stages of simple retinitis 



DISK ASKS OK TIIK KKTINA. 



423 



there may be increased visual acuity, although this is more com- 
mon with retinal irritation than with inflammation. 

(2) Change in the Field of Vision. — This may be irregularly 
or concentrically contracted, or scotomata may appear in its 
centre. 

(3) Distortion of Vision. — This occurs under two forms: («) 
( objects appear to be reduced in size (micropsia); (6) objects appear 
to undergo change in their contour or shape (metamorphopsia). 
Vertically-placed parallel lines, on the one hand, appear to be 
bulged outward, and on the other to be bent inward. Fine 
parallel lines may appear icavy to a normal eye. 

Fig. 133. 




Distortion of vertically-placed parallel lines in retinitis (Loring). 

(4) Pain and Photophobia. — Acute pain is almost always ab- 
Bent even in violent forms of retinal inflammation; indeed, it is 
much more likely to be present in the less pronounced grades. 
Usually the sensation is one of discomfort rather than of actual 
j iain. Photophobia may or may not be present. It is never a 
marked sign, although comfort ensues from the use of tinted 
glasses. 

Diagnosis. — The diagnosis of retinitis depends upon the 
essential symptom of the disease — opacity or loss of transparency 
in the retina. All the other symptoms which may be present — 



424 DISEASES OF THE EYE. 

exudation, hemorrhages, pigmentation, and atrophy — help to 
make up the clinical characteristics of the various types, but in 
themselves are not diagnostic of inflammation of this membrane. 

Much diagnostic aid is obtained by noting the effect of the 
disease upon vision, especially under the influence of diminished 
illumination, and when acuity of sight fails quite out of propor- 
tion to the amount of the light reduction, the student should at 
once be upon his guard. If the coarse changes detailed in the 
general symptom-grouping are present, the picture is readily in- 
terpreted. 

Course, Complications and Prognosis. — The course of a 
retinitis, like any other inflammation, may be acute or chronic, 
and its progress of long or short duration. When the retina and 
choroid are simultaneously inflamed, a common complication is 
change in the vitreous (vitreous opacities), and an almost con- 
stant association is inflammation of the optic papilla, leading to 
atrophy in prolonged cases (retinitic atrophy). 

The prognosis may be either favorable, grave, or positively 
fatal, depending upon the extent of the inflammation, its situa- 
tion in the inner or outer layers of the retina, and the cause. 
Before giving a prognosis, the surgeon must always attempt to 
estimate the extent of the permanent disability which is likely 
to remain in the form of atrophy of the membrane, or secondary 
changes in the papilla. Other things being equal, the prognosis 
of syphilitic retinitis is the most favorable. 

Treatment. — This, in general terms, demands perfect rest 
for the inflamed organ. In sthenic cases, in the early stages, 
blood-letting from the temple is indicated. 

The remedies most likely to afford relief are the various forms 
of mercury, iodide and bromide of potassium, ergot, and occasion- 
ally jaborandi and Turkish baths. Special methods of treatment 
are reserved for the sections devoted to the several clinical varieties. 

Serous Retinitis (Retinitis simpler, Diffuse I'd in it is, (Edema 
of the Retina). This disease is characterized by an infiltra- 
tion, especially of the nerve-fibre and ganglionic layer of the 
retina, causing opacity and oedema, together with hypera^mia, mi fif 
marked in the veins. 

The opacity varies from a delicate veiling to a decided gray- 



DISEASES OF TIIK RETINA. 



425 



white opacity, most noticeable around the nerve-head, the margins 

of which arc veiled or hidden. From this point, the grayish 
opacity shades out into the surrounding retina. The disc is not 
swollen, it is simply hidden by the (edematous infiltration, or, if 
the oedema is not marked, it is very red and its margins obscured 
by the radiation of finely-injected capillaries from its margins. 
The veins are dark, fuller than normal, tortuous, and often partly 
covered by the swollen tissue ; the arteries are not much changed 
in size, unless perchance they may be reduced in calibre by com- 
pression. Hemorrhages are rare, and exudations in the macular 
region are uncommon. 

Fig. 134. 




Serous retinitis (modified from Meyer). 

There are no external signs of this form of inflammation. 
Both direct and indirect vision are affected, the former being 
" foggy ;" the latter concentrically contracted. 

Cause. — Independently of the fact that it may be the initial 
change of other forms presently to be described, this type has 
been ascribed to cold, to exposure, to undue light and heat, 



426 DISEASES OF THE EYE. 

and to the influence of refractive error in eyes worked under the 
disadvantage of imperfect illumination. In other cases it is quite 
impossible to assign a reason for its development. 

Treatment. — This is conducted on the general principles 
already laid down. 

Parenchymatous Retinitis. — By this term is understood those 
forms of retinitis in which, in addition to oedematous infiltra- 
tion, opacity of the retina and venous hyperemia, there is pro- 
nounced cellular infiltration and structural change leading finallv 
to atrophy of the elements. 

Exudations of yellowish or gray color are visible, occurring in 
patches throughout the eye-ground, and often localized in a cha- 
racteristic manner in the macula. Small hemorrhages are com- 
monly present, and the morbid processes may attack the sheaths 
of the vessels, causing thickening and hypertrophy. 

There are no diagnostic external manifestations. Deeply 
seated pain of a dull, aching character may be present. Vision 
is often much disturbed, varying from a mere fogginess in the 
outlines of objects to an almost absolute loss of sight. Contraction 
of the field of vision and positive scotomata are demonstrable, and 
the phenomena of distortion of objects are apparent. The disease 
may be circumscribed or diffuse, and localized in the external or 
internal layers, or affect both of these and also involve the choroid. 

Prognosis. — This is always grave, and although in certain 
cases absorption of the products is possible, compression and 
atrophy of the nervous elements must result in most instances. 

Cause. — The various constitutional complaints, disturbances 
of the uterine functions, and intracranial disorders, are the mosl 
prominent causes. 

Treatment is governed by the probable exciting cause, 
together with proper rest for the eyes. 

Partaking of the nature of one or the other of these forms 
there are certain clinical types : — 

Syphilitic Retinitis. — The syphilitic forms of retinal inflam- 
mation have been divided by Alexander into (a) ehoroido-retinitis; 
(b) simple syphilitic retinitis; (c) retinitis with exudations; (d) reti- 
nitis with hemorrhages; and (e) central relapsing retinitis. 

The first form is really a disease of the choroid, and the patho- 



DISEASE- OF THE RETINA. ll'T 

logical changes of cellular infiltration, exudation, atrophy, and 
proliferation of the pigment epithelium are found in the choroid, 
between the choroid and retina, and in the adjacent retinal layers. 

The following signs are visible: Opacity of the vitreous, 
especially in the posterior portion, which resolves itself into fine 
points or dust-like particle-, and stretches out to the periphery 
like a cloud ; loss of transparency of the retina surrounding the 
nerve-head which may be unduly hyperseniic, and on account of 
the tine opacity in the vitreous, may give the impression that it is 
swollen ; numerous yellowish or wdiite spots of exudation bounded 
by pigment beneath the vessels of the retina in the periphery of 
tin' eye-grounds, and white spots in the macula ; and, finally, occa- 
sional participation of the iris and posterior layer of the cornea. 

The subjective symptoms are : Depreciation of central vision, 
very marked in the later stages; night blindness and great less- 
ening of visual acuity under weak illumination; irregular and 
concentric contraction of the visual field and the formation of 
ring scotomata as well as positive scotomata in the centre of 
the field ; and shimmerings, dancing spots and circles (pho- 
topsies), and distortion of objects in the form of micropsia and 
metamorphopsia due to separation of the rods and cones by the 
effusion. 

In the second form there appears to be a localization of the 
disease in the retina, and the ophthalmoscope reveals a gray 
opacity surrounding the nerve-entrance, this opacity stretching 
out in lines along the vessels ; the papilla is discolored, cloudy, 
and has been compared to a yellowish-red, oval body seen through 
a covering of fog. The veins are darker than normal, the arte- 
ries usually are not materially changed. 

Other objective symptoms are floating vitreous opacities, exu- 
dations along the lines of the vessels (retinitis with exudations), 
and extravasations of blood, usually round in shape, attributed 
to disease of the vessel walls (endarteritis), or to the formation of 
thrombi {retinitis with hemorrhage). Hemorrhages in syphilitic 
retinitis, however, are of rare occurrence. 

Date of OCCURRENCE. — Diffuse syphilitic retinitis may occur 
in congenital and acquired syphilis. In the acquired form of the 



428 DISEASES OF THE EYE. 

disease it appears from one to two years after infection, sometimes 
as early as the sixth month, and is found in about eight per cent, 
of tlie cases (Alexander). One eye alone may be affected, but 
usually after several months the second eye is also involved. 

True retinitis must not be confounded with the so-called " reti- 
nal irritation" commonly seen in association with iritis, and the 
symptoms of which have been described under hyperemia. 

Coukse and Prognosis. — Although the onset of syphilitic 
retinitis may be sudden, the course is essentially chronic. 

The prognosis largely depends upon the stage at which treat- 
ment is begun and the vigor of the measures employed. De- 
layed or neglected treatment may lead to the grave conse- 
quences of extensive choroiditis, pigmentary degeneration in the 
retina, and atrophy of the optic disc. Even under favorable 
circumstances improvement may be temporary and many stub- 
born relapses occur. 

Treatment. — The same constitutional measures recommended 
in the treatment of syphilitic iritis are applicable. Bleeding from 
the temple has been recommended, but it is difficult to understand 
upon what grounds. 

Central Relapsing Retinitis (Retinitis macularis) is the last form 
of syphilitic retinitis which requires mention. It belongs to the 
late manifestations of syphilis, and appears in the form of a 
gray or yellow area in the macula, or as numerous small, yellow, 
or yellowish-white spots and pigment dots, or as a diffuse opacity 
of this region. The papilla and its surroundings are unaffected. 
A characteristic of the disease is its frequent relapses. It is a 
rare form of syphilitic retinitis, and stubborn in its character. 

Purulent Retinitis (S<j>tie Retinitis). — This term has been ap- 
plied to an affection seen in pysemia, puerperal septicaemia, putrid 
bronchitis, and other pyogenic conditions, and is characterized by 
small, circumscribed white spots near the papilla and in the 
macular region. Usually both eyes are involved, and numerous 
small hemorrhages may be seen. These spots are due to fatty 
degeneration of the capillaries and infiltration of the retinal 
fibres, and have been attributed to a change in the composition 
of the blood and to emboli of bacteria. 



DISEA8ES OF THE RETINA. 42!) 

Suppurative choroiditis, described on page 355, may begin in 
the retina with plugging of the vessels, opacity of the layers and 
hemorrhages, and under such circumstances may be looked upon 
as the violent form of purulent retinitis, or, as it is sometimes 
called, embolic panophthalmitis. Unlike the first variety described, 
a single eye is commonly affected, although both may suffer. 
A- Luring suggests, the more frequent use of the ophthalmo- 
Bcope during septicemic conditions would probably disclose the 
earlier symptoms of this affection, before the vitreous becomes 
filled with pus, rendering a view of the fundus impossible. 

Anatomical investigations have shown that an independent or 
primary purulent retinitis may occur in an acute form from a 
penetrating foreign body, and in a chronic form, presenting the 
clinical picture of suppurative choroiditis. 

Treatment. — In the severe forms which pass into a general 
ophthalmitis, treatment is practically of no avail ; indeed, in 
pyemic conditions, these are a precursor of death. In the milder 
forms, the prognosis is not so unfavorable, and recovery from the 
causative disease may take place. 

Hemorrhagic Retinitis. — Although, the mere presence of 
hemorrhages in the retina does not necessarily mean the coexist- 
ence of retinitis, if signs of inflammation are added, the term 
hemorrhagic retinitis is suitable. 

In a typical case, the appearances are as follows : Swelling of 
the papilla, its edges being clouded or hidden by an opaque infil- 
tration of the surrounding retina ; darkly tortuous and distended 
veins, but small arteries; and numerous hemorrhages, either 
linear, flame-shaped, or, when lying in the deeper layers, irregular 
and round in appearance. 

The size, number, diffusion and localization of the hemor- 
rhages vary. Thus, they may be everywhere throughout the eye- 
ground, or grouped especially in the macular region, or around 
the papilla. If white spots are present as the result of degene- 
ration after absorption of the blood, the appearances may closely 
resemble those seen in so-called renal retinitis, which, indeed, 
may be one of the types of hemorrhagic retinitis. 

CAUSES. — Hemorrhagic retinitis occurs with diseases of the 
heart and of the bloodvessels, e. r/., hypertrophy, aneurism, and 



430 DISEASES OF THE EYE. 

endarteritis; in suppressed menstruation; at the climacteric; and 
in a variety of general and local diseases, sometimes presenting 
types presently to be described under special clinical designation.-. 
More rarely, retinitis with hemorrhages is caused by secondary 
syphilis. 

The hemorrhage in most instances is due to rupture of small 
vessels, whose coats have become degenerated; in other cases, 
it has been ascribed to diapedesis of the blood corpuscles. The 
disease is often monocular. No doubt in many cases the pres- 
ence of the hemorrhages determines the retinitis by causing 
irritation of the retinal fibres, and in this sense, both the extra- 
vasation and the inflammation are symptoms of the vascular dis- 
ease, which is the primary affection. 

Prognosis. — This is unfavorable, both as to sight and because 
the ocular condition may indicate a grave vascular or cardiac 
malady, and may be the forerunner of extravasations in vital 
centres. Secondary changes in the retina and optic nerve are 
likely to follow ; sometimes glaucoma results. 

Treatment. — In addition to local depletion from the temple 
and protecting the eye with dark glasses, the therapeutic measures 
must be governed by the general condition. Often iodide of 
potassium is indicated, with or without cardiac sedatives. Ergot 
has been recommended, and also small, not diaphoretic, doses of 
pilocarpine. Any congestion of the portal circulation, which in 
itself may originate the disorder, should be regulated by suitable 
laxatives. 

Albuminuric Retinitis [Renal retinitis, Papitto-retinitis, Reti- 
nitis of BrigMs disease). 

Symptoms. — In a typical case, beginning in the macula or its 
immediate neighborhood, and continuing to be most numerous in 
this region, variously shaped and placed white spots appear. 
These at first may be small, discrete, and sharply separated, but 
later, or under other conditions, they form a somewhat star-shaped 
figure, the rays of which surround the fovea, but for the most 
part do not involve it. Occasionally, instead of a stellate arrange- 
ment, the white spots and lines, somewhat radially placed like 
spokes in a wheel, affect this neighborhood in part, but do not 
completely encircle it. 



DISK ASKS OF TDK RETINA. 



i.;i 



At some distance from the papilla, and often surrounding it, 
larger yellowish-white or white spots are seen, which may coalesce 
and form a ring-shaped zone around the nerve-head, broader than 
it- own diameter. This striking, wide, white area has been com- 
pared to snow, and designated " the snow bank appearance of 
the retina." 

The fine white spots in the macula are due to fatty infiltration 
of the inner ends of the supporting fibres (Mueller's fibres), and 




Albuminuric retinitis (De Wecker and Masselon). The white spots represent 
areas of fatty degeneration ; the dark spots, hemorrhages. A somewhat star- 
shaped figure occupies the macula. 

in general terms, the white spots are caused by fatty degeneration 
of the fibre and granular layers of the retina, round cell infiltra- 
tion, and varicose hypertrophy of the nerve fibres. 

A nother feature, but unlike the white spots having no pathogno- 
mic appearances, are the hemorrhages. They may be linear, flame- 
shaped, or round, or mere flecks scattered here and there, and found 
with difficulty, or they constitute large, dark-red extravasations. 
Moreover, they are not constant, like the white spots, but at times 
disappear, leaving white marks which denote their former situa- 
tion. Sometimes they occur in great numbers, like fresh ex- 
plosions. To a certain extent, they are indications of the vio- 
lence of the disease. 



432 DISEASES OF THE EYE. 

The bloodvessels may run over the white plaques, or mav be 
buried in the swollen retina. Sometimes a vessel disappears 
beneath the infiltration, to reappear at some distance beyond 
The veins are dark and often tortuous ; the arteries, as in other 
forms of retinitis, are not materially altered in size. In the later 
stages the vessels exhibit lack of transparency of their walls, in 
the form of white tissue along the sheaths, or they are actually 
converted into white strings. 

Finally, the optic papilla and its immediate surroundings, 
may partake of the nature of an intense hypercemia, or a swell- 
ing of the nerve-head occurs, quite indistinguishable from that 
of optic neuritis, as it is seen in tumor of the brain. Under 
any circumstances, the edge of the papilla is clouded, but not 
necessarily swollen, the surrounding retina finely clouded, and 
traversed with numerous radiating injected lines, like those de- 
scribed in other types of retinitis. Quite commonly the changes 
in the papilla directly join the band of fatty infiltration, already 
described, surrounding the end of the optic nerve. 

The chief, in fact the only, subjective symptom is depreciation 
of vision, which may vary from a slight and gradual impairment 
to complete blindness. It is a well-known fact that Bright's 
disease is often discovered by an ophthalmoscopic examination, 
the patient being ignorant of the fact that he is the subject of 
serious organic malady. 

Forms of the Disease. — Two varieties have been recog- 
nized — an inflammatory and a degenerative type. Often the two 
are combined. 

The former may be present as violent neuro-retin it is from the be- 
ginning, or it may start as a degenerative type, and assume inflam- 
matory action. The latter begins without inflammatory changes, 
the white spots are small, often quite minute, and separated by 
comparatively normal areas, and the hemorrhages, if present, are 
inconspicuous, being confined largely to the nerve-fibre layer. If 
hemorrhages are the most conspicuous feature of the disease, the 
term hemorrhagic is applied; if the changes are almost wholly 
confined to the optic papilla, the neuritie type is developed. 

It is probable that in some instances single small hemorrhages 
and comparatively insignificant dots in the macula may be the 



I) IS J VSKS <)F THE RETINA. 



433 



fflgns of renal retinitis, and consequently of renal disease. In 
every ease of retinal disease the urine should be frequently and 
thoroughly examined. 

Causes. — While in general terms, so-called Bright's disease 
is the cause of the retinitis which bears its name, it most fre- 
quently occurs with the type in which the chronic granular kid- 
ney is the chief lesion. It may also arise with large white 
kidney, and with lardaeeous disease, but is rare in the latter. 
The retinitis seen with pregnancy is most commonly due to 
albuminuria, and the disorder is also found with scarlatinal 
nephritis. In a few cases functional albuminuria causes retinal 
changes. Almost invariably both eyes are involved, but in rare 
instances the affection has been monocular. The author has ob- 
served one such case, which, however, was not examined post 
mortem. 

Course, Complications and Prognosis. — The course of 
typical renal retinitis has been divided into the stage of hyper- 

FiQ. 136. 




Albuminuric retinitis in a late stage. The white dots represent the spots of 
fatty change, and are most numerous in the macula (De Wecker and Jaeger). 



semia of the papilla, opacity of the retina and hemorrhages ; the 
stage of fatty degeneration ; and the stage of retrograde meta- 
morphosis and atrophy. 

28 



434 DISEASES OF THE EYE. 

The white spots may subside, but rarely disappear entirely, 
the macular changes being most permanent. (Fig. 136.) Dis- 
coloration and atrophy of the papilla, contraction of the vessels 
and the formation of white tissue along their walls, and pigment 
changes in the retina finally result. 

Detachment of the retina, hemorrhage into the vitreous, em- 
bolism and thrombosis of the vessels, extravasations into the 
choroid, and rarely glaucoma, have been described as complica- 
tions of this affection. 

The prognosis, as far as vision is concerned, is most unfavor- 
able, except in the mildest forms, not only on account of the 
sequential changes, but also because of the direct involvement of 
the macula. In so far as the life of the patient is concerned, 
albuminuric retinitis is a most unfavorable symptom, and the 
large majority of the patients die within two years after its ap- 
pearance, prolongation of life to the end of five years being 
exceedingly rare. 

In the albuminuric retinitis of pregnancy the prognosis in 
regard to vision and the life of the patient depends upon the 
duration of gestation. With the termination of pregnancy the 
inflammatory deposits (the type most often is inflammatory) 
may subside, and good vision may be restored, provided the pro- 
cess has not continued so long that the secondary changes already 
described have taken place. For this reason the induction of 
premature labor has been recommended as a therapeutic measure. 

Diagnosis. — In widespread cases of albuminuric retinitis, the 
changes detailed in the symptom-grouping are quite character- 
istic, and may be said to be pathognomonic of kidney disease. 

Xeuro-retinitis from intracranial disease may simulate this affec- 
tion, and often only a careful study of the urine and the general 
symptoms will establish the diagnosis. The question become- 
still more complicated if albuminuria is associated with brain 
tumor. 

In glycosuria and leucocythaemia somewhat analogous appear- 
ances are found, and again an examination of the urine, as well as 
that of the blood, may be necessary before reaching a diagm 

The white spots are distinguished from plaques of choroidal 
atrophy by the absence of pigment-heaping. The snow-bank 



DISEASES OF THE RETINA. 435 

appearances differ from retained marrow sheath (page 454), by the 
tad that the latter stretches away from the margin of the disc, usu- 
ally ending in a fan-shaped border, and is unaccompanied by 
the changes in the macula, or bv retinal cedema. Fine lesions of 
the choroid in the macular region may be mistaken for some- 
what similar retinal changes; but they are more scattered, more 
yellow in color, usually unassociated with distinct loss of vision, 
and less liable to assume a stellate or radial appearance. 

TREATMENT. — Local measures are practically of no avail. 
The case must be managed on the general principles suited to 
the form of kidney disease which is present. A proper remedy 
in most cases is iron, usually in the form of the tincture, and 
often advantageously combined with bichloride of mercury. 

Diabetic Retinitis. — This occurs in several forms. It is always 
bilateral, but there are no pathognomonic signs. 

Hirschberg describes two varieties of diabetic retinitis — an 
exudative and a hemorrhagic form. They are late manifestations 
of diabetes, and are seen at a time when gangrene, carbuncle, 
hemiplegia, and other serious complications of this disorder arise. 
In any case of diabetes of long duration retinitis is seldom 
absent, although it may sometimes be difficult to find the lesions, 
because they exist in the periphery of the eye-ground. This is 
especially true if the complication of high myopia, or cataractous 
lens, is present. 

Much more commonly than in the retinitis of albuminuria, 
opacities and hemorrhages occur in the vitreous humor. The 
student should never neglect to make an examination for sugar 
in the urine in any case in which he finds hemorrhagic retinitis, 
or small hemorrhages associated with white spots of exudation, 
especially around the macula. 

Treatment. — There is no local treatment. The discovery of 
such a condition may lead to the finding of sugar in the urine, 
but more commonly the patient is already conscious of his dis- 
ease and i- under medicinal and dietetic treatment. 

Leucocythaemic Retinitis. — The retinal chauges seen in splenic 
leucocythsemia, to which variety of the disease they are almost 
exclusively confined, affect both eyes, usually one more than its 
fellow. 



436 DISEASES OF THE EYE. 

The most important ophthalmoscopic appearances are slight 
swelling of the papilla, pallor of its surface, veiling of its edges, 
and some opacity of the retina, especially along the lines of the 
vessels. The latter present a striking appearance. The veins 
are broad, distended, and of a somewhat rose-red color; the arte- 
ries, in contrast, narrow and orange-yellow, which color substi- 
stntes the ordinary fiery red of the choroid, the vessels of which, 
if they are visible, present a yellowish-red tint. 

Very prominent lesions are white spots with red borders, espe- 
cially near the equator and in the region of the macula lutea. 
The spots vary in size and are often somewhat elevated in appear- 
ance. They are due to a collection of lymph corpuscles, ami the 
red border to an extravasation of blood corpuscles. 

On the other hand, retinitis associated with leucocythsemia 
may not present characteristic appearances, but consist simply 
of a diffuse opacity of the retina, or appear in the form of 
hemorrhagic retinitis. When the yellow 7 spots which have been 
described develop in the macula, it is sometimes difficult to dis- 
tinguish the case from one produced by albuminuria. Indeed, 
albumin in the urine may be present with leucocythsemia. In 
any doubtful case, a careful blood examination will reveal the 
true nature of the disease. 

In addition to the types of retinitis thus far described, there 
are certain rare forms. 

Proliferating Retinitis. — This is a development of connective 
tissue in the retina, and consists of dense masses of bluish-white 
or white color, which are developed from the retina and stretch 
out into the vitreous humor. They often cover a considerable 
portion of the fundus and hide the papilla, which may with diffi- 
culty be seen through the intervening spaces. Sometimes tli< 
masses follow in the course of the bloodvessels, which in part 
may lie beneath them and in part pass over them ; those which 
lie above the masses are occasionally newly-formed bloodvessel-. 
As complicating circumstances, there may be detachment of the 
retiua, opacity of, and hemorrhage into, the vitreous. The dis- 
ease is said to be most common in young people, and may result 
from an inflammation, but may also develop from repeated hem- 
orrhages. A similar retinitis is ascribed to oxaluria. 



DISEASES OF THE RETINA. 137 

Retinitis Circinata. — This name is applied by Fuchs to cases 
characterized by a concentric arrangement of white spots around 
the macula, composed of fibrinous exudation. De Wecker, how- 
ever, denies the special character of the disease, which he attrib- 
utes to hemorrhages. 

Central Punctate Retinitis ( Retinitis punctata albescens). — This 
peculiar type of retinal affection, originally described by Mooren, 
occurs in middle-aged or old people, and is under the influence of 
no known dyscrasia. 

A great number of stria? or spots, resembling in color the 
reflex of the sclera are visible. The retinal vessels are not covered 
by the spots, and the papilla shows but slight changes. The 
peripheral field of vision is unaffected ; in the centre there may 
be a scotoma. Sometimes vitreous hemorrhages occur. Athero- 
matous changes in the vessels elsewhere in the body are found. 

Treatment. — This consists in depletion from the temple, 
and iodide of potassium or other alterative of similar physiologi- 
cal action. 

Pigmentary Degeneration of the Retina (^Retinitis pigmentosa). 
— Although this affection is usually entitled retinitis pigmentosa, 
the phenomena of inflammation are absent, and it consists of a de- 
generation of the nerve tissue, associated with great contraction of 
the bloodvessels and the accumulation and deposition of pigment 
of well-nigh characteristic form, in the substance of the retina. 

Symptoms. — The ophthalmoscopic appearances of a typical 
case are as follows : — 

(a) Pigmt mtatUm. — The pigment masses assume an appearance 
resembling bone corpuscles, and by the frequent union of their 
processes, simulate the Haversian canals. By preference, the pig- 
mentary depositions are more marked on the temporal side. 
They begin far out in the periphery of the eye-ground, often 
lying along the course of the main vessels, and gradually approach 
the papilla, the macula region remaining for a long time unaf- 
fected. A zone midway between the centre and far periphery 
is the favorite seat of pigmentation. 

(b) "Wainscotted Fundus." — A perfect picture of the appear- 
ance already described in connection with superficial choroiditis 
is visible on account of the absorption of the retinal pigment epi- 



438 DISEASES OF THE EYE. 

thelium and the exposure of the larger vessels of the choroid. 
The overlying retina is distinctly gray. 

(c) Contraction of the Vessels. — This is present in both sys- 
tems. The vessels may be as thin as threads. Often their walls 
exhibit patches of opacity, and they are accompanied by fine 
white lines. Not only are they greatly contracted, but they are 
apparently diminished in number. 

(d) The Changed Nerve-head. — The color of the papilla, accord- 
ing to the stage of the disease, is of a yellowish-gray, yellowish- 
red, or waxy tint. It finally becomes dull white and atrophic. 
Except a slight veiling, its edges are plainly marked. 

Fig. 137. 




Pigmentary degeneration of the retina (Jaeger). 

(e) Opacities of the Media. — Posterior polar cataract may be 
a complication. Opacities in the vitreous are very uncommon. 

(f) Nystagmus. — Quite frequently a quick lateral oscillation 
of the eyeballs, or nystagmus, is present, especially in congenital 
cases. 

The subjective symptoms are : — 

(a) Depreciation of Central Vision. — Visual acuity maybe but 
slightly affected in the earlier stages, although usually the per- 
ception of green and red is below the normal (Oliver). Indeed, 



DISEASES OF THE RETINA. 139 

reasonably good central vision may remain, even when the clis- 
ease is very widespread, but it finally sinks with the progress 
of the affection. 

(b) Contraction of the Field of Vision. — This is concentrieally 
contracted according to the amount of degeneration, and the 
contraction may be so excessive that only a very small area of 
the field remains. In rare instances, even with extreme nar- 
rowing of the visual field, there is still moderately good central 
vision, and the patient may read by fixing a single word at a 
time. Finally, the contraction goes on to complete blindness. 
The defect in the field may also be irregular, according to the 
position of the areas of degeneration, and it sometimes assumes 
the form of a broad, ring-seotoma. 

(c) Night Blindness. — Often this is the first symptom which 
calls attention to the case. The patient is uncertain in his 
movements and stumbles as soon as twilight begins, becoming 
quite helpless in the dark. Night blindness is not always pres- 
ent, and in rare instances diminished light is a relief to the pa- 
tient. Such a condition is due to retinal hyperaesthesia. 

Atypical Types. — The pigment may be massed in the mac- 
ular region. Then the central vision is much affected, and a 
scotoma appears around the point of fixation. In other instances 
the pigment masses are scattered all over the fundus in irregular 
masses, and are associated with clear, shining spots lying beneath 
the retinal vessels. Cases occur presenting the usual subjective 
symptoms, but without the accumulation of pigment — really 
forms of sclerosis of the retina without the formation of pig- 
ment — and a few instances, associated with a broad peripheral 
zone of choroidal atrophy, have been described. Finally, in 
rare instances, retinitis pigmentosa may be complicated with 
chronic glaucoma, the retinal affection probably antedating the 
glaucoma (Bellarminoff, Mandelstamm). 

Causes. — The disease is markedly hereditary. In numbers 
of instances, consanguinity of the parents of the patient has been 
found ; indeed, the disease has been attributed to this alone. 
Hereditary syphilis has been given as a possible cause of retinitis 
pigmentosa, but this has not been proven. The affection is found 
among deaf-mutes, idiots, and epileptics, and in this sense is con- 



440 DISEASES OF THE EYE. 

nected with morbid states of the nervous system. Very often 
no cause can be assigned. The disease is either congenital or 
begins in childhood. 

Its pathological anatomy has not been definitely settled. There 
is a sclerosis of the connective tissue of the retina and a wander- 
ing forward of the hexagonal pigment, but it is not quite certain 
whether the beginning of the disease is in the superficial layers of 
the choroid, or in the pigment epithelium. It is always bilateral. 

Diagnosis. — A fully formed and typical case of retinitis pig- 
mentosa presents no difficulties in diagnosis. It may be distin- 
guished from disseminated choroiditis by the difference in the 
pigmentation of the two diseases. 

Its differential diagnosis from certain types of retino-choro- 
iditis seen in acquired syphilis is difficult, especially when the 
latter manifest themselves in the form of atrophy of the retina 
and a gathering of pigment spots, beneath which the exposed 
choroidal vessels are visible. In retiuo-choroiditis, however, the 
pigment spots do not have the characteristic form ; they are much 
scattered, and do not follow the bloodvessels ; besides vitreous 
opacities, which are very rare in pigmentary degeneration of 
the retina, are usually present. 

A patient complaining of night blindness, or seen stumbling 
about during the twilight, should be subjected to a careful ex- 
amination of the far periphery of the eye-ground, if necessary 
after dilatation of the pupil, because occasionally the pigment i- 
confined to this region and might be overlooked by a careless 
observer. 

Course and Prognosis. — The course of pigmentary degener- 
ation of the retina having begun in childhood, progresses steadily 
onward with ever-increasing contraction of the field of viaioD 
until finally, usually by middle life, sight has been obliterated, 
with, perhaps, the exception of a slight eccentric preservation of 
the field. The prognosis is hence unfavorable under all circum- 
stances and in spite of all known endeavors to modify the course 
of the disease. Occasionally, when the pigment accumulation 
has advanced far over the retina, but the macula still is free, the 
disease remains stationary for long periods of time. 



DISEASES OF THE I : I. TIN A. 



Ill 



TREATMENT. — This is of little avail. Strychnia in full doses, 
especially by the hypodermic method, has beeD recommended. If 

there is any suspicion of syphilitic taint the usual remedies are 
applicable. Galvanism has been tried, and under its influence 
it is stated that the progressive contraction of the field of vision 
ha- been stayed, although no improvement in the acuity of cen- 
tral sight was obtained. It certainly should be given a trial in 
every case. 

Detachment of the Retina (Ablatio retinas ; Amotio retinas). — 
Idiopathic separation of the retina from the underlying choroid, 
is due to an accumulation of a serous fluid, between these mem- 
brane-. 

Symptoms. — The student will observe, as he examines the 
various portions of the fundus, with the ophthalmoscope (direct 
method), an alteration of refraction at the area of separation ; the 
surface of the elevation thus produced being out of focus as com- 
pared with the rest of the eye-ground. Thus, if the general 



Fig. 138. 




Detachment of the retina (De Wecker and Masselon). 

fundus is hypermetropic, the detached portion will be more hyper- 
metropic, and require a stronger convex glass for the study of 
its surface ; if it is highly myopic, a weaker concave glass, or, it 
may be, a low convex lens. 



442 DISEASES OF THE EYE. 

The normal color of the fundus is lost as the detached retina 
is approached, which appears as a gray or bluish-gray membrane 
stretching forward into the vitreous, containing folds which give 
rise to a sheen. The intervening furrows present a greenish-gray 
reflex, and the whole oscillates with the movements of the eye 
when the underlying substance is fluid ; if it is a solid, neither 
folds nor tremulousness are present. Rents in the detached retina, 
through which the choroid is visible, are often demonstrable. 

The retinal vessels rise over the separated portion, first lose 
the light streak, and finally appear as dark tortuous cords (Fig. 
138). They apparently are of smaller size than normal, and 
when followed backward they pass out of focus at the edge of 
the detachment, which is usually sharply marked from the normal 
fundus; indeed, there may be a yellowish border and occasionally 
accumulated pigment. The amount of discoloration of the de- 
tached area depends upon whether the case is recent or not, and 
upon the character of the underlying substance. In the earlier 
stages the transparency is not lost and the gray color, previously 
described, may not be present. 

The detachment, either partial or complete, may occupy any 
portion of the fundus, but most commonly is found below, even 
when it has begun in the upper part. Sometimes the detach- 
ments are quite small, like a series of furrows, and at other times 
an almost circular circumscribed separation occurs. Finally, the 
subjective signs of detachment may be present without discover- 
able elevation of the retina, but over the area (which subse- 
quently separates) there is complete loss of the light reflex from 
the retinal vessels (Loring). 

Unless the macular region is directly involved, vision is not 
obliterated, but there is always interference with sight. This 
may develop suddenly. The field of vision is lost in an area 
corresponding to the detached retina, and the completely dark- 
ened portion is usually bordered by a zone of imperfect vision 
corresponding to an area of retina not yet separated, but elevated 
above its normal plane. If the retina is detached below, the 
upper portion of the visual field is obliterated; if above, the 
lower portion, and so on. (Fig. 139.) 

The patients complain of distortion of objects (metamor- 



DISK ASKS OF TI1K KKTINA. 



44:} 



phopsia); of floating spots before the eyes, due to the frequent 
presence of vitreous opacities; of au appearance like a cloud, 
due to the scotoma produced by the separated area; and of phos- 
phenes, although the latter cannot be elicited by pressure on the 
eyeball over the separated area. 



Fig. 139. 






Various types of fields of vision in detachment of the retina. 

CAUSES. — The causes of retinal separation are : High (malig- 
nant) myopia; traumatisms; effusion of blood, preceded usually 
by hemorrhages into the vitreous or retina ; intraocular tumors 
(sarcoma of the choroid) or subretinal parasites (cysticercus) ; 
tumors and abscesses in the orbit; and diseased conditions of the 
eye as retinitis, cyclitis, irido-cyclitis, etc. In the last instance 
the detachment is found after removal of the shrunken globe. 
More men than women are affected, myopic refraction most fre- 
quently is present, and the separation is more apt to occur in an 
eye in which the visual disturbance has rapidly developed. The 



444 DISEASES OF THE EYE. 

condition may become apparent suddenly, especially after sudden 
effort, or arise slowly. 

Mechanism. — Leber and Nordenson hold that the first process 
is a fibrillar change in the vitreous, which shrinks and occasions 
traction. This ruptures the retina, and the fluid from the vitreous 
cavity passes beneath it through the opening. The primary cause 
of the pathological alteration in the vitreous is believed to be dis- 
ease of the choroid and ciliary body. Raehlmann explains the 
detachment by a diffusion theory analogous to transudations in 
other parts of the body. 

Diagnosis. — No difficulty arises in detecting a large detach- 
ment of the retina by attending to the symptoms already detailed. 
An extensive or complete detachment which floats far forward 
may be examined by oblique illumination. When the vitreous 
is full of opacities, a study of the field of vision is useful. When 
the substance underlying the detached portion is fluid, there are 
usually diminished tension of the eye-ball, and the appearance 
of furrows in the separated tissue, which trembles with the 
movements of the eye, symptoms which are absent when a solid 
growth has caused the separation. Important diagnostic points 
are the loss of the light reflex of the vessels, and their dark 
color over the area of separation. They can be seen to regain 
the light reflex in passing over the normal retina. 

Prognosis. — This is very unfavorable, and many of the sug- 
gested means of treatment have proved unsatisfactory. In rare 
instances, there is spontaneous re-attachment of the retina. 

Treatment. — This should include rest in the prone position 
and the use of a pressure bandage, associated with pilocarpine- 
sweats. The iodides and salicylic acid may be tried, and improve- 
ment after instillations of eserine has been reported. The author 
has tried eserine and had one good result. Repeated small dos< - 
of salicylic acid appear to act favorably in some cases. 

Various forms of operative procedure have been attempted : 
sclerotomy and iridectomy, the latter certainly should be con- 
demned; evacuation of the subretinal fluid by puncture and 
aspiration; and drainage by means of a gold wire. Recently 
Schdeler has reported successes by the injection of iodine and the 
production of sufficient inflammation to reunite the choroid with 



DISEASES OF THE RETINA. 



445 



the separated retina. This method should be rejected from the 
domain of ophthalmic surgery (Bull). In cases of detachment 
due to tumor, the question of enucleation is to be considered. 

Certainly in spontaneous or traumatic detachment, the sub- 
retinal contents being fluid, it' a compressing bandage, instilla- 
tions til' eserine ami pilocarpi ne-sweats should prove unavailing, 
scleral puncture and evacuation of the fluid, followed by a careful 
rest treatment, is a rational procedure. 

The following phenomena arc especially concerned with patho- 
logical changes in the blood itself, the peri-vascular tissues and 
the vessel walls, and are indicative both of local disease or, as 
in many of the inflammatory stages, of disease in distant organs : — 

Hemorrhages in the Retina (Apoplexy of the Retina). — The 
appearances of retinal hemorrhage have been described in the 
general symptom-grouping, and as they occur with so-called 
hemorrhagic retinitis. 



Fig. 140. 




Retinal hemorrhages (De Wecker and Masselon). 

Hemorrhages (unassociated with inflammation) may be in any 
of the layers of the retina, or, bursting through the limiting 
membrane, they may occupy the vitreous humor. By preference 
they are found along the course of the larger vessels; a favorite 



446 DISEASES OF THE EYE. 

site is the macula. Hemorrhages originating in the outer sheath 
of the optic nerve may appear at its margin and spread into the 
surrounding retina. 

Hemorrhages of large dimensions and drop-like form usually 
mean an extravasation between the internal limiting membrane 
of the retina and the hyaloid membrane of the vitreous, and they 
come from a retinal vessel (usually a vein). These sub-hyaloid 
hemorrhages tend to occur at the yellow spot more than at other 
parts of the fundus. 

Causes. — Some of these have already been enumerated. The 
following resume, based upon the classification of Dimmer, may 
be added : — 

(«) Hemorrhages caused by changes in the composition of the 
blood and the tissues of the bloodvessel walls : Pyaemia, septi- 
caemia, ulcerating endocarditis ; diseases of the liver, spleen, 
kidney, and atheroma of the vessels ; loss of blood (menorrhagia, 
haematemesis) ; anaemia (simple and pernicious), haemophilia, pur- 
pura, and scurvy ; diabetes and gout ; malaria and recurrent fever. 

(6) Hemorrhages caused by disturbances in the circulation : 
Hypertrophy of the heart and stenosis of the valves; thrombosis 
of the central vein of the retina, and embolism of the central 
artery; suffocation, compression of the carotid, and hemorrhages 
in the newly-born ; and the menstrual disturbances. 

(c) Hemorrhages caused by sudden reduction of the intraocular 
tension; e. g., after iridectomy in glaucoma, and by traumatisms. 
Among the latter may be classed retinal hemorrhages after large 
cutaneous burns. 

Prognosis. — This depends upon the extent and situation of 
the hemorrhages. 

Hemorrhages form a prognostic guide of the disease which has 
caused them, and, in elderly people, may be a warning of future 
hemorrhages into the brain. Hemorrhagic glaucoma, detachment 
of the retina, and the formation of dense opacities in the vitreous 
humor may be complications. 

Treatment. — All use of the eyes must be forbidden. Locally, 
a weak solution of sulphate of eserine may be employed, especially 
in elderly people. Internally, the medication must be governed 
by the probable cause. Frequently, cardiac sedatives, ergot, 



DISEASES OF THE RETINA. 



447 



-mull doses of pilocarpine, and later, alteratives, like iodide of 
]x .ta-li and bichloride ofmercory, will be required. 

Changes in the Retinal Vessels and their Walls. — Independ- 
ently of the various grades of dilatation and contraction of the 

-Is, t<> which reference has been made, certain other changes, 
due to vasculitis and peri-vasculitis, are seen. 

The so-called peri-vasculitis is characterized by the appearance 
of white stripes along the vessels, or, rather, the vessel walls be- 
come apparent by their conversion into whitish tissue, due pro- 
bably to an infiltration of the adveutitia with lymph corpuscles. 
This may be so extensive that the entire set of vessels is con- 
verted into a series of branching white lines. 

Fig. 141. 




in the retinal 

upward are coi 



v white hands. 



Peri-vasculitis, thinning and atrophy of the vessels, together 
with thickening of their walls, are due to various inflammatory 
diseases of the retina and optic nerve. 1 



1 Alternate contractions and widening of the calibre of the vessels, together 
with undue tortuosity and grayish reflections from their walls, have been de- 
scribed in connection with general arterial sclerosis. Conversion of one or 



448 DISEASES OF THE EYE. 

Aneurisms. — Aneurism of the eentral retinal artery is an 
extreme rarity. It has been seen as a spindle-shaped sac, pul- 
sating synchronously with the heart. Miliary aneurisms, usu- 
ally spindle-shaped, have been noted in the small arterial twigs, 
and may be looked upon as significant of a similar condition of 
the vessels in other organs, especially the brain. The student 
should not mistake varicosities in the veins for aneurisms. Arte- 
rio-venous aneurism of the retina has been described as the result 
of injury (Fuchs). 

Embolism of the Central Artery of the Retina. — An embolus 
may lodge in the central artery of the retina, or in one of its 
branches. 

Symptoms. — The main branches of the artery are thin, and 
can be followed only a short distance over the edge of the papilla 
into the retina, and there is a diminution in the number of rami- 
fications. The veins are also contracted, and very often they 
present unequal distension. They may present ampulliform 
broadening, alternate contractions and swellings, and especially 
a contraction at the disc, succeeded by broadening in the peri- 
phery, where they assume almost their natural breadth. There 
is no change of diagnostic significance in the color of the blood. 
Pressure from before backward, so as to increase the intra- 
ocular tension, causes a regular current to flow through the ves- 
sels. This consists of broken cylinders of blood, separated by 
clear spaces, which move sluggishly along. In the veins, with- 
out such pressure, and, it may be, directly after the accident, an 
intermittent blood stream is often visible. The appearance is not 
unlike that produced when air is allowed to mix with a fluid in 
a tube. Occasionally a few hemorrhages are seen along the course 
of the vessels. 

The papilla assumes a pallid, grayish-white appearance, owing 
to the lack of blood in its capillaries. An opacity in tin retina 

more vessels into white cords, among the larger ones of which a thin blood 
stream may be seen, while the smaller ones are collapsed, has been attributed 
to endarteritis obliterans. Glistening white patches on the principal arteries, 
associated with opacity of the papilla, have been ascribed to the formation of 
granular deposits of lime. Pigment stria- may appear in the retina after hemor- 
rhage, followed by hyperplastic changes in Mailer's fibres (l'lange) — the cmgioid 
streaks of Knapp. 



DISEASES OF THE RETINA. 449 

develops in the form of a grayish-white, fog-like oedema, some- 
times permitting the reddish tint of the normal eye-ground 
to shine through it, and sometimes being so opaque tliat it 
is quite milk-like in its density. This occurs especially in the 
neighborhood of the papilla and in the macular region, the space 
between the two often being free, although gradually the areas 
meet. The opacity comes on within a few hours after the acci- 
dent, or may be delayed for a day or two. The author has 
watched it form within twenty minutes after the lodgment of 
an embolus. 

Characteristic of sudden obstruction of the arterial circulation, 
is the formation in the macula lutea (corresponding to the posi- 
tion of the fovea) of a central red spot, which resembles a round 
hemorrhage in the midst of the milky-white ©edematous area. 
It is known as the cherry-red spot of the macula lutea, and is 
caused by the red color of the choroid appearing through the 
much thinned retina, and changes in the pigment epithelium. As 
a rare complication, at least in the dark-skinned races, the usual 
cherry-red spot has been replaced by a coal-black one. The spot 
appears at the same time with the opacity in the macula lutea. 
It is less likely to form where there is a stoppage of a branch 
of the retinal artery instead of one of the main trunks. 

In the course of several weeks there is a gradual subsidence of 
the retinal oedema, the optic disc undergoes atrophy, and the re- 
tinal vessels ai'e shrunken or even converted into white cords; if 
there have been hemorrhages, spots of degeneration appear at 
their positions, and not infrequently cholesterin crystals and pig- 
ment markings may be seen around the disc and in the macula 
lutea. 

Instead of the main trunk, a branch may receive the embolus, 
which, in some instances, actually becomes visible to the ophthal- 
moscope as a yellowish body, but, more frequently, is assumed to 
be present because at one point in the artery there is a swelling, 
while beyond it there is complete obliteration of the vessel, or its 
reduction to an extremely thin calibre. The secondary retinal 
changes are then confined to the area supplied by this vessel. 

Vision is lost with characteristic suddenness. Occasionally, 
preceding the blindness, there is some uncertainty in vision, or 
29 



450 DISEASES OF THE EYE. 

a little headache and giddiness, with flashes of light, representing 
a species of aura. In obstruction of a branch by an embolus, 
on the other hand, there may be very good acuity of vision. 
Indeed, in some instances, even in embolism of the upper branch 
of the central artery, this has been normal. The presence of a 
dlio-rdinal vessel may be the means of preserving good acuity 
of vision. 

The field of vision varies according to the extent of the block- 
ing of the circulation. In cases where the obstruction is com- 
plete, even light perception is absent. If only a branch has been 
occluded, that portion of the retina which receives its blood sup- 
ply from this source will be paralyzed, and the opposite area of 
the field will be darkened. The presence of a cilio-retinal vessel 
permits, as a rule, an oval portion of the field of vision to remain 
in the neighborhood of the fixation point. Even if the main 
stem of the artery is obstructed, a portion of the nasal retina 
may retain its functional activity. An uncommon eifect is a 
central scotoma. 

The intraocular tension is sometimes raised, sometimes lowered, 
and sometimes unaffected. The pupil may be large and irre- 
sponsive to light, if the case is one of complete stoppage of the 
central artery. 1 

Causes. — The most frequent cause of embolism of the central 
artery of the retina is valvular disease of the heart, especially if 
complicated by a fresh endocarditis. It also occurs with general 
arterial sclerosis, aneurism of the aorta or of the carotid, and 
with Bright's disease and pregnancy ; in a few instances, it has been 
noted with chorea. It may occur at almost any age of life and 
has been recorded from the fifteenth to the eightieth year. The 
accident usually is unilateral, simultaneous embolic plugging of 
the central artery of each eye being very rare. 2 

Diagnosis. — The ophthalmoscopic picture just detailed indi- 
cates that there has been an interruption in the retinal circulation, 

1 The symptoms which have heen described refer to typical cases ; a variety 
of exceptions occur. 

2 In a certain number of cases, although all of the ordinary ophthalmoscopic 
appearances of embolism of the central artery of the retina have been present, 
it has been impossible to assign a cause. 



DISEASES OF THE RETINA. 431 

but docs not prove that the stoppage has been due to embolism. 
Similar appearances occur with thrombosis, and with hemorrhage 
into the sheath of the optic nerve. Thrombosis of the central 
vein, moreover, may be so situated as to press upon and occlude 
the lumen of the artery lying beside it. This still further com- 
plicates the diagnosis. Certain points of difference will present ly 
lie mentioned. 

Prognosis. — This is exceedingly unfavorable, and in most 
instances blindness is the result. Even when temporary im- 
provement occurs, subsequent atrophy of the nerve is likely to 
ensue. In embolism of a branch, the prognosis is more favor- 
able, and, as has been stated, normal central vision may be 
present. The presence of a cilio-retinal vessel improves the 
prognosis. 

Treatment. — This does not often prove of avail. In the 
hope of restoring the circulation by reducing the intra-ocular 
tension, sclerotomy, iridectomy, and repeated paracentesis of the 
anterior chamber have been practised, but without success. 
Vigorous kneading or massage of the eyeball has been recom- 
mended, and in some cases has been followed by good results. 
It should be given a faithful trial. With the massage, inhala- 
tions of nitrite of amyl may be given (Gifford). 

Thrombosis of the Retinal Artery. — This may occur in heart 
disease, disease of the bloodvessels, and alteration of the compo- 
sition of the blood. The ophthalmoscopic picture does not differ 
from that described under embolism. The symptoms upon which 
a differential diagnosis may be attempted are stated by Priestley 
Smith to be : Previous attacks of temporary blindness in the 
affected eye, a simultaneous attack of temporary blindness in the 
unaffected eye, and giddiness, faintness, and headaches — symp- 
toms which are absent in embolism. 

Treatment. — This is the same as that recommended for 
embolism. 

Thrombosis of the Central Vein. — This has been observed a 
number of times as the result of a phlebitis, and, also, with heart 
disease when embolism might have been suspected. 

In some instances, the appearances have been closely similar 
to those of embolism ; in others, they have assumed an inflamma- 



452 DISEASES OF THE EYE. 

toiy character similar to that described under hemorrhagic reti- 
nitis, of which it may be a cause. Several grades of this condi- 
tion have been recorded. If, in addition to the ordinary dis- 
turbances present in embolism, the ophthalmoscope reveals 
tortuosity of the vessels, engorgement of veins, and normal or 
contracted calibre of the arteries, venous pulse, and interrupted 
venous circulation and retinal hemorrhages, thrombosis of the 
central vein may be suspected (Angelucci). 

Traumatisms of the Retina — Under this general term may 
be included traumatic anaesthesia, traumatic amblyopia, detach- 
ment, and rupture. There are no characteristic symptoms com- 
mon to all varieties, but pain, and disturbance of vision, in part 
due to the direct injury, and in part to a transient astigmatism, 
are likely to be present. 

(1) Traumatic Anaesthesia is the name proposed by Leber for 
those cases occurring after a blow upon the eye without discover- 
able ophthalmoscopic changes, but with considerable defect in 
vision and contraction of the visual field — defects, moreover, 
which may remain unchanged for a long time, or, indeed, never 
entirely pass away. 

The treatment is rest and the use of strychnia internally, or 
by hypodermic medication. 

(2) Traumatic Amblyopia (Commotio Hetince, CEdema of the 
Retina) is a condition also arising from an injury, especially a 
blow from a ball, cork, or similar body, and is attended by the 
following symptoms : Hypersemia of the globe marking the 
position of contact of the missile ; clear media ; and gray opales- 
cence of the retina, especially in the macular region, but also 
around the papilla, which may be somewhat hypersemic. If the 
retina under the point of contact is visible, this also may exhibit 
the white infiltration. In addition, several pale yellowish spots, 
and, occasionally, small hemorrhages may be present. The vessels 
are unchanged, or, in some instances, are contracted (arteries), or 
distended (veins), and pass over the gray area. A central scotoma 
may exist. 

An interesting complication is the development of a transitory 
astigmatism, which helps to reduce the visual acuity. 

The gray infiltration forms quickly and is also absorbed with 



DISEASES OF THE RETINA. 453 

rapidity, usually having subsided at the end of two or three 

davs, although the visual defect may last for longer periods. 
Decided retino-choroiditis, the result of concussion, may occur, 
and this fact should U> remembered in investigating old cases of 
choroidal disease presenting themselves with meagre history. 

The treatment consists in keeping the pupil dilated with atro- 
pine and covering the injured eve with a shade or dark glass, all 
use of the uninjured organ being forbidden. 

(3) Detachment of the Retina after injury has been mentioned. 

(4) Rupture of the Retina. — Rupture, uncomplicated by cho- 
roidal fissure, the result of injury, is a rare accident, and might 
be recognized by observing the frayed edges of the tear and seeing 
the exposed choroidal tissue. Loring describes such an occur- 
rence following a fall upon the back of the head. 

Retinal Changes from the Effect of Sunlight (Solar Retinitis). 
— It has been experimentally proven that retinal changes can be 
produced in animals' eyes by concentrating upon them the rays 
of the sun. Clinically, analogous disturbances have been found 
in the human retina after exposure to intense light, most fre- 
quently in those who, with unprotected eyes, have watched an 
eclipse of the sun. 

The symptoms are : Persistence of an after-image or later a dark 
spot in the field of vision (positive scotoma), distortion of objects, 
and evidences of slight retinitis or retino-choroiditis in the macular 
region. Thus, there may be a maroon-colored area with a central 
gray patch, and numerous faintly-marked yellowish-white dots. 

The prognosis for decided improvement is favorable, but com- 
plete recovery is exceptional (Mackay). The scotoma may be 
permanent (Duane). 

Glioma of the Retina. — Gliomata are tumors having as their 
prototypes neuroglia-eells, and ordinarily are found in the brain 
and spinal cord. A tumor composed of cellular elements occurs 
in the retina resembling the cells of its granule layer, and, accord- 
ing to some pathologists, should be classed as a sarcoma, although 
its clinical characteristics are very different from those presented 
by the usual forms of the latter growth. 

According to the layer of the retina from which the growth 
takes its origin, it has been described by systematic writers as 



\')\ DISEASES OF THE EYE. 

glioma endophytum and glioma exophytum. In the former, the 
vitreous chamber is occupied by the growth ; in the latter, it lies 
between the retina and choroid. 

The tumor is usually of a light-gray or grayish-red color. It 
is subject to various degenerative changes — fatty, cheesy, and 
calcareous — and tends, on the one hand, to invade the orbit, 
involve the optic nerve, and travel by the way of its sheath to 
the brain, and, on the other, to pass forward, bursting through 
the sclerotic and cornea. Recurrence in loco after extirpation 
may occur, and metastases, although not common, do take place. 

Like sarcoma of the choroid, it passes through several stages. 
In the first, there are no signs of irritation, the media are clear, 
the pupil is dilated, and often the growth produces a whitish reflec- 
tion which has given rise to the designation amaurotic cat's eye. 
As the disease progresses, symptoms of irritation and increase in 
the size and tension of the globe become manifest, and the process 
begins to involve the optic nerve. Finally, the tumor bursts from 
its bounds, perforates the globe at its corneo-scleral junction, grows 
rapidly, involving the orbit and neighboring temporal regions, 
and presents a huge vascular mass, to which, in former times, 
the name fungus hainatodcs was applied. 

Glioma of the retina is either congenital or occurs in infancy. 
It may occur as late as the eleventh year. It is not a common 
affection. Hereditary disposition has not been established. Sev- 
eral members of the same family may be affected. One or both 
eyes are likely to be involved. 

Diagnosis. — The following conditions, according to E. T. 
Collins, may be mistaken for glioma : Persistence of the poste- 
rior part of the foetal fibro-vascular sheath of the lens ; masses 
of tubercle in the choroid; inflammatory or purulent effusioE 
into the vitreous following retinitis or cyclitis, usually with de- 
tachment of the retina (see also Pseudo-glioma, p. 407). In 
glioma the anterior chamber is uniformly shallow ; in inflamma- 
tory exudates into the vitreous the chamber is deepened at it- 
periphery (retraction of iris) and shallow at its centre (bulging of 
pupillary border). Synechia? are occasionally present in glioma. 
T is usually increased in glioma, but may be minus ; rarely the 



DISEASES OF THE RETINA. 455 

tension is elevated In pseudo-glioma. In case of doubt the e}-e 
should be enucleated. 

Sarcoma of the choroid is differentiated from glioma by the fact 
that the former usually occurs at a later period of life and that in 
the earlier -tages of each affection the ophthalmoscopic findings 
are different. In glioma the tumor is seen to involve the retinal 
structure which does not, as in sarcoma, merely act as a covering 
to the growth. 

Prognosis. — This is unfavorable, and if the disease has 
involved the optic nerve or bursts from its bounds, it is fatal. 
Still, numbers of recoveries are on record, and an opinion must 
be based on the extent of the disease, the condition of the optic 
nerve being the most important element in the prognosis. Recur- 
rence is rare after three years of immunity. Iu a number of 
fatal cases which have been aualyzed (Lawford, Collins) the optic 
nerve was unaffected in only four. Under unfavorable circum- 
stances recurrence iu the orbit occurs, with extension to the brain, 
and, more rarely, metastasis to a distant organ. 

Treatment. — Thorough enucleation, with division of the 
optic nerve as far back as possible, is the only treatment. Any 
suspicious tissue in the orbit is to be sacrificed. In several in- 
stances both eyes have been removed, and recovery after such 
procedure has been recorded. 

Subretinal Cysticercus. — This, like the presence of the same 
parasite in the vitreous, is exceedingly uncommon in this country. 

Symmetrical Changes at the Macula Lutea in Infancy. 
— This rare disease was first described by Waren Tay, and con- 
sists of a grayish-white zone about the size of the papilla in 
each macular region, with a cherry-red spot in the centre, closely 
resembling the appearances seen in embolism of the central artery. 
Kingdon has thus summarized the general clinical signs : mus- 
cular enfeeblement, apathy, mental weakness, and gradual loss of 
sight. Death occurs in from one to two years. The autopsies 
show a change in the pyramidal cells of the cortex and degen- 
eration of the cord. According to Sachs, this is au arrest of 
development. The author has studied one case in the hospital 
practice of his colleague, Dr. B. Alex. Raudall. 



456 DISEASES OF THE EYE. 



CHAPTER XVI. 

DISEASES OF THE OPTIC NERVE. 

Congenital Anomalies. — Opaque or MeduUated Nerve Fibres. 
— In the normal eye the fibres of the optic nerve cease to be in- 
vested with a medullary sheath at the lamina cribrosa, and conse- 
quently the axis cylinders, which are distributed to the retina, are 
transparent. As an anomalous condition, sometimes bilateral, but 
more frequently only in one eye, the medullary sheaths reappear 
at the upper or lower margin of the disc as a dull or glistening 
bluish-white patch, which extends for a variable distance out into 
the retina, and ends in a somewhat feathery or fan-shaped margin. 
Usually the retinal vessels are hidden by the patch, but reappear 
again on its distal side. 

This plaque may be a single one above or below, or it may 
appear both above and below the disc, more rarely on the nasal 
side, and very exceptionally, if ever, upon the temporal margin. 
The size varies from a small expansion to a huge sweep of white 
tissue, continuous above and below with margins of disc, and 
taking somewhat the general direction of the vessels, which arc 
wholly or in part concealed. 

This condition produces no change in vision, except an increase 
in the size of the normal blind spot, and should not be mistaken 
by the beginner for pathological lesions, for example, an atrophy 
of the retina and choroid, or a bank of fatty degeneration as it 
occurs in retinitis albuminurica. 

Coloboma of the Sheath of the Optic Nerve. — This congenital 
anomaly is characterized by an apparent augmentation of the 
surface of the disc, and an excavation of the papilla backward 
and downward. The periphery is usually bounded by pigment 
massing. There is an unequal division of the retinal vessel-, 
which are first seen as they bend over the margin of the exca- 



DISEASES OF THE OPTIC NERVE. 157 

vation. It is a rare anomaly, and has been mistaken for poste- 
rior staphyloma. It depends upon imperfect closure of the foetal 
fissure. 

Irregularities in the Disc — Instead of its usual round or oval 
Bhape, the disc may be markedly irregular in outline, one side 
being occasionally at an apparently lower level than the other, 
or it may present a gibbous appearance. 

When the nerve-head fails to fit the choroidal aperture accu- 
rately, a space is sometimes formed, usually crescentic, known 
as a " cone" or " conns" (Loring). This generally is seen at the 
outer side of the papilla, but also inward, below, and very rarely 
above. It should not be confused with the cases of atrophy 
of the choroid seen in myopic eyes, to which the name posterior 
staphyloma is given (page 354), nor with the crescents of cho- 
roiditis seen in astigmatic and stretching eyes, in which the scleral 
ring broadens out into a semi-atrophic area of disturbed choroid, 
usually bounded by an irregular pigment line, and most com- 
monly developed at the temporal side of the disc. 

Shreds of Tissue on the Disc. — These appear as glistening white 
patches of tissue, sometimes almost transparent, at other times 
thicker and more opaque, either completely or partially hiding the 
vessels (De Beck). Occasionally, there is a white membrane, 
more or less completely covering the disc. 

It seems most probable that these represent remains of the 
hyaloid artery, or appearances of its adventitious coat. 

Hyperaemia of the Nerve-head (Congestion of the Disc). — 
The color of the intraocular end of the optic nerve varies con- 
siderably, and it is not accurate to describe a nerve-head as con- 
gested when it simply is redder than usual. 

As Gowers points out, the term simple congestion is applicable 
when the papilla presents a dull red or brick-dust hue, which 
shades almost imperceptibly, through a blurred margin, into the 
general red color of the fundus ; when it is more marked in one 
eye than in the other, the latter serving as a picture for compari- 
son ; when at some antecedent examination the same optic disc 
has presented a more natural color; and when its borders are 
obscured, but not hidden. 



458 DISEASES OF THE EYE. 

Under other circumstances — and the appearance is a frequent 
one — the surface of the nerve is covered by an overlying semi- 
transparent or cedematous layer, appears unduly injected, and its 
margins, especially the nasal ones, are veiled by retinal striations 
of mixed, fine grayish lines, and minute capillaries ordinarily not 
visible. The peri-vascular lymph sheaths at the same time are 
unduly prominent in the form of white lines along the central 
vessels, especially the veins. 1 

Causes. — (a) Refractive error, especially hypermetropia and 
hypermetropic astigmatism. In this connection, however, the 
caution of Loring should not be forgotten that the retinal stria- 
tion and increased vascularity may be due to the presence of 
unusual amounts of connective tissue and the additional vascu- 
larity common to hypermetropic eyes. 

(6) Prolonged exposure to glare and heat. 

(c) Certain toxic agents presently to be described, and inflam- 
mation of the iris, usually of the syphilitic type. 

(d) Certain disorders of the brain, especially various types of 
chronic insanity. It is extremely difficult, however, to decide 
whether congestion is caused by a cerebral condition, because 
under ordinary circumstances increased vascularity of the papilla 
is not an index of hyperemia of the cerebral vessels. 

Treatment. — This depends entirely upon the cause. Refrac- 
tive error should be corrected, if this is the apparent origin of the 
trouble. Constitutional measures will be required if there is 
reason to believe that some general cause is at work. Mild 
cholagogues or saline waters are excellent adjuvants under any 
circumstances. 

Anaemia of the Nerve-head. — This is not a disease peculiar 
to the optic nerve, but like retinal ansemia, occurs as part of a 
general anaemia, or because of obstruction to the central vessels, 
for example in embolism. 

It is most difficult to interpret the significance of pallor of the 
papilla. Usually it will require more than mere inspection to 
decide whether or not a pallid disc is pathological. 

1 This appearance has received the name "hypermetropic disc." 



DISEASES OF THE OPTIC NERVE. 459 

I. Intraocular Optic Neuritis (Papillitis, Neuritis, Choked 
Disc). — Under the general term papillitis are included the various 
types of inflammation, cither with or without the appearances of 

mechanical congestion, seen at the intraocular end of the optic 
nerve. 

Symptoms. — Certain symptoms arc common to all types of 
optic neuritis : — 

(1) Changes in the Nerve-Head. — («) Increased redness of the 
disc and obscuration of its borders. 

(/>) Swelling of the disc, loss of the light spot, complete hiding 
of the margins, the centre usually remaining redder than the 
periphery, which has a grayish tint and shades gradually in 
a descending slope into the surrounding retina. The swelling 
increases, assumes a mound-shape of mixed grayish color, and 
finally the form of the disc is lost, and its position can be inferred 
only by the convergence of the vessels. This swelling is measur- 
able by the table given on page 119, and by the parallactic test. 
White spots and patches are often seen in the elevation, sometimes 
covering the retinal vessels. (Fig. 142.) 

(2) Changes in the Vessels. — The arteries, smaller than nor- 
mal, pursue a moderately straight course and are difficult of 
recognition, being always partly concealed by the swelling. 
Occasionally, spontaneous pulsation is visible. The veins are 
dark in color, distended and tortuous, and pass along the slope 
of the elevation, often dipping into the infiltrated tissue. The 
light streak is not lost, at least not where the vessel is clearly 
visible. 

The tortuosity of the vessels is sometimes remarkable, and 
has been compared to the writhing snakes in the Medusa-head. 
The point of emergence and convergence of the vessels may be 
hidden by the infiltration, so that the centre of a papillitis seems 
somewhat destitute of vessels. In some instances thickening of 
the adventitia of the vessels gives rise to the appearance of white 
lines along their sides. 

(3) Hemorrhages. — In many cases hemorrhages are found 
upon the swollen papilla, or in its immediate neighborhood. 
They are in the form of narrow, flame-shaped extravasations, 
if they lie in the fibre-layer, but may also assume other shapes, 



460 



DISEASES OF THE EYE. 



if situated in a deeper plane. The number varies from a single 
hemorrhage to so many that the swollen nerve-head assumes a 
hemorrhagic form, or the surrounding retina may be freely occu- 
pied by elongated or other-shaped patches of blood. 



Fig. 142. 
-.*.•>;»«»:' .--"re. 



'&&M$&k 




Schematic representation of the ophthalmoscopic picture of papillitis, and a 
longitudinal section of the nerve-head (Schmidt-Rimpler). 



In addition to the ophthalmoscopic changes just detailed, the 
following points deserve notice : — 

(1) The Vision in papillitis may be entirely unaffected. This 
is an important fact, and the mere presence of good central sight 
should never be considered cause to omit ophthalmoscopic ex- 
amination. Usually one eye is more affected than its fellow. 
Impairment of sight may come on rapidly or slowly. Occasion- 
ally vision is lost with great suddenness, but this is rare. 



DISEASES OF THE OPTIC NERVE. 



461 



(2) The Field of Vision. — The field of vision presents for con- 
sideration its periphery, which may at first be unaffected and 
later show irregular and concentric contraction ; the increase in 
the size of the normal blind spot, which becomes correspond- 
ingly great in comparison with the amount of swelling; the 
formation of an abnormal blind spot or scotoma due to involve- 

Fig. 143. 




Abnormal size of the blind spot in papillitis. The central darker area represents 
the normal blind spot (reduced about .10) placed there for comparison. 

ment of the axial fibres ; the absence of half of the visual field 
(hemianopsia) when the intracranial mischief which may have 
been the cause of the papillitis is so situated as to produce this 
phenomenon; and finally, defective color- percept ion, which may 
exist when there is no change in central vision and no limita- 
tion of the form-field. As in other pathological conditions, the 
perception of red and green is usually lost before that of other 
colors. 

(3) External Appearances. — There are no changes in the ex- 
terior of the eye indicative of swelling or inflammation in the 
nerve-head. There are no characteristic pupillary phenomena. 
If blindness is complete the iris is immobile. 

(4) Symptoms of Irritation are practically absent. 

Forms of Intraocular Neuritis. — Papillitis presents itself 
in different forms, and on this account, in former days, two 



462 DISEASES OF THE EYE. 

chief types were described, choked disc and descending neuritis, to 
which a third, or rather a different form of the second type, 
namely, neuro-retinitis, may be added. 

When the symptoms were confined to the intraocular end of 
the optic nerve, and consisted of enormous swelling, giving the 
impression of mechanical compression, great distension of the re- 
tinal veins, and hemorrhages, the name choked disc was applied, 
and is constantly employed at the present day to describe that 
form of papillitis which is seen with brain tumor. 

When the symptoms consisted of a moderate swelling and 
no unusual filling of the veins, but, on the other hand, of an exu- 
dation which produced discoloration and opacity of the papilla, 
and which was not sharply limited to it, but passed into the 
surrounding retina — the term descending neuritis was applied. 

If an extensive participation of the retina was found, with 
hemorrhages along the vessels, spots of degeneration in the eye- 
ground, sometimes collected in a star-shaped figure and analogous 
to the appearances described under renal retinitis, the condition 
received the name of neuro-retinitis. 

To avoid confusion of names, as well as to escape unproven 
theories in pathology, Leber proposed the general term papil- 
litis. 

In rare instances, papillitis is confined to a single eye. 

Diagnosis. — The diagnosis of papillitis depends upon a direct 
ophthalmoscopic examination of the inflamed disc. The method 
of determining the height of the elevation has been explained. 

The student should not mistake the slightly prominent discs 
that are occasionally seen in hypermetropia for papillitis. 
There may be a superficial neuritis in hypermetropia, and under 
these circumstances it is difficult at times to decide whether 
the disc has become inflamed under the influence of an intra- 
cranial disease or general trouble, or whether it is congested as 
the result of eye-strain. For this reason, one of the symptoms 
of intraocular neuritis, namely, redness of the disc, is not a suffi- 
cient one upon which to base a diagnosis. 

Course, Complications, and Prognosis. — There are seve- 
ral grades of papillitis. The first stage usually is not, as might 
be expected, a simple congestion of the end of the optic nerve, 



DISEASES OF THE OPTIC NERVE. 163 

although preceding an actual intraocular neuritis there may be 
very marked tortuosity of the retinal veins, even before any 
obscuration of the disc itself is observed. 

Ciowers has divided papillitis into the first stage, or the stage 
of congestion with oedema, and the second stage, or that of true 
neuritis, or papillitis. 

The most important symptoms of the first stage are indicated 
by the name which it has received. It presents different appear- 
ances, as Gowers has further pointed out, to the direct and in- 
direct examination ; in the former, the blurring of the edges of 
the disc is complete ; in the latter it is not complete, and the mar- 
gins may be seen through the cloudiness. 

In the stage of true papillitis, the symptoms before mentioned 
in reviewing the general symptom-group occur. 

The course of the disease is a very variable one. Occasionally 
swelling of the intraocular end of the nerve will come on with 
great rapidity ; in other instances, it is slow in its course and 
lasts for months and even years, with progressive failure of vision. 

When the evidences of inflammation and oedema begin to 
subside, the veins grow less distended, no new hemorrhages 
appear, or at least rarely, vessels previously obscured by the 
swelling begin to reappear, especially in the centre of the projec- 
tion, which becomes depressed. The mixed grayish-red tint 
becomes more uniformly gray, and grows paler and paler, the 
borders of the disc begin to be visible, usually first upon the 
temporal side, uutil finally all margins again are apparent, at 
first a little mellowed, while the centre is still covered by the 
former inflammatory tissue. Finally, the edges of the disc are 
clear, its color is white and atrophic, and its centre becomes ap- 
parent. Both sets of vessels are contracted, and often contain 
along their sides whitish tissue. Areas of retino-choroiditis and 
elevated patches of degeneration, marking spots of former hemor- 
rhages, are often apparent. Second attacks of neuritis may occur, 
as in a case observed by the author and A . Thomson. 

Before a prognosis can be given, the cause must be definitely 
ascertained. If this, as for instance in the neuritis which occurs 
as the result of removable syphilitic deposits, is amenable to 
treatment, excellent results may be obtained. 



464 DISEASES OF THE EYE. 

Causes. — The most common cause of papillitis is tumor of the 
brain. The development of papillitis does not depend upon the 
size of the growth nor upon its situation, except that the morbid 
growths of the medulla are said not to originate optic neuritis. 
Tumors of the convexity of the brain are less liable to produce 
intraocular neuritis (Edmunds and Lawford), and those of the 
cerebellum are more liable to cause papillitis, especially of an 
intense type, having the characteristics to which the older writers 
applied the term choked disc. All types of morbid growth may 
originate papillitis — fibroma, sarcoma, glioma, carcinoma, solitary 
tubercle, and gummata. It also appears with echinococcus cysts, 
hematoma of the dura mater, and abscess of the brain. 

Next in frequency to the various forms of brain tumor as a 
cause of papillitis is meningitis, especially when this is localized 
at the base of the brain, and is of tubercular origin. The ap- 
pearances of the disc often assume those which have been called 
descending neuritis and neuro-retinitis. When there is direct 
pressure upon the tracts and chiasm, the swollen papilla has a 
peculiar gray- white color, without much vascularity. 

Other intracranial causes are softening of the brain, cerebritis, 
hemorrhage (very rare), thrombosis of the cavernous sinus, hy- 
drocephalus (uncommon), and aneurism. 

In rare instances myelitis, general paresis, epilepsy, and dis- 
seminated sclerosis are accompanied by optic neuritis. 

In addition to the intracranial causes of papillitis, this phe- 
nomenon may arise as a symptom of: (1) Acute febrile affec- 
tions — typhus fever, variola, scarlatina, diphtheria, etc. ; (2) 
syphilis, both because of the formation of an intracranial pro- 
duct (gumma), or as an essential sign of the disease ; (3) toxic 
agents, like lead ; (4) anaemia, both when this is an essential pro- 
cess and when it is caused by excessive hemorrhage ; (5) disturb- 
ances of menstruation ; (6) exposure to cold, and rheumatism 
(sometimes monolateral) ; and (7) injuries. Papillitis occasionally 
occurs as a congenital affection in several members of the same 
family, and as an idiopathic disease without evident cause. 

Finally those cases of neuritis arise which depend upon dis- 
ease of the orbital region — inflammation of its contained tissues, 
tumors, caries, and periostitis, especially around the optic fora- 



DISEASES OF THE OPTIC NERVE. 165 

men, purulent disease of the antrum of High more and the 

frontal -inns, and morbid processes of the sphenoid and ethmoid 
bone. In niost of these instances, unless both orbits are affected, 
the papillitis is unilateral, and there are other symptoms around 
the eye which point to the local condition. 

A rare form of optic neuritis is that described in association 
with persistent dropping of a watery fluid from the nose. 
Headache, vomiting, unconsciousness, and delirium are present. 
The fluid has been believed to be identical with the cerebro-spinal 
fluid (Leber), or to be due to nasal disease in the form of small 
polyps (Xettleship and Priestley Smith). 

Treatment. — This depends entirely upon the cause of the 
papillitis. In all syphilitic cases rapid mercurialization should 
be tried, followed later by the iodides. Indeed, in non-syphilitic 
cases, these remedies are often indicated for their alterative action. 
In ameniia, iron and arsenic should be exhibited ; in rheumatism, 
the salicylates, iodides, and pilocarpine ; in menstrual disturb- 
ances, measures for the promotion of the catamenial flow, if this 
has been suppressed. Orbital disease calls for appropriate sur- 
gical measures, and in high grades of papillitis, with distension 
of the optic sheath, several surgeons have exposed this, slit it, 
and evacuated the contained fluid, in the hope that thus a cause 
of mechanical compression would be removed. 

Mechanism of Papillitis. — Theories Concerning the Jlechan- 
ism of Papillitis. — As is well known, von Graefe at one time 
sharply distinguished between descending neuritis and so-called 
choked disc (" Stauimgs-papiMe "). The former indicated a descent 
of inflammation from the seat of disease along the optic nerve to 
its intraocular tip. The latter was reserved for a condition sup- 
posed to indicate by its appearance engorgement, oedema, and 
mechanical obstruction, and to represent a mechanism and path- 
ology quite different from those ascribed to the former. 

Inasmuch as ophthalmoscopically it is frequently impossible to 
tell one from the other, and as the conditions may be mixed, it is 
best to coincide with the opinion of Hughlings Jackson, that 
there is one kind of optic neuritis from intracranial disease which 
mav manifest itself under different appearances, sometimes with 
and sometimes without "swelling of the disc." 

30 



466 DISEASES OF THE EYE. 

The following are the most important theories of the mechanism 
of papillitis: 

(a) The Bach-water Theory, propounded by von Graefe, taught that 
through increased intracranial pressure there was compression upon the 
cavernous sinus, which induced venous congestion in the central vessels 
of the optic nerve, because the passage of blood returning from the eye 

Fig. 144. 




Optic nerve and posterior portion of eyeballs in situ (the orbital plate has been 
broken in and the fat removed). The distension of the sheath of the optic nerve, 
especially on the left side, is noticeable as a swelling behind the sclera. The case 
was one of cerebellar tumor in a child four years old in the Children's Hospital. 

was hindered, and that this congestion was increased by the rigid scleral 
ring which acted as a multiplier. This theory ceased to be tenable when 
Sesemann demonstrated the anastomosis between the ophthalmic and the 
anterior facial veins. 

(b) The Lymph-space Theory arose after the demonstration by Schwalbe 
and Retzius of the lymphatic circulation of the eyeball and the commu- 
nication between the subarachnoid space and the intervaginal sheath of 
the optic nerve. First Schmidt-Rimpler, and later Manz, ascribed to the 
dropsy of the inter-sheath space of the optic nerve, which is caused by 
the increased subarachnoid fluid being forced into this situation under 
the influence of elevated intracranial pressure, a mechanical or com- 
pressing action, or to the fluid which found its way into the lymphatic 
spaces of the optic disc an action causing oedema, congestion, and inflam- 
matory symptoms. 

(c) The Vasomotor Theory was first suggested by Schneller, and has 
been advocated by Benedict and Hughlings Jackson. To use Jackson's 
words, " Optic neuritis may be a doubly indirect result of local gross 
organic disease; that first there are changes of instability about the 
tumor ' H that next these lead on discharges, by intermediation of vaso- 
motor nerves, to repeated contractions, with subsequent paralyses, of 
vessels of the optic nerves or centres, and thus, at length, to that trouble 



DISEASES OF THE OPTIC NERVE. 467 

of nutrition which is optic neuritis." This hypothesis has few followers 
..[i account of the lack of anatomical demonstration of such a mechanism. 

(d) The Inflammatory Theory, with various modifications, assumes, as 
Leber suggested and Deutschmann afterward experimentally showed, 
that papillitis is not a product of (edema, but an inflammatory affection, 
the fluid which distends the sheath of the nerve possc->inir an irritative 
quality ; or. in other words, that the subarachnoid fluid is infected by 
products from the intracranial disease or lesion which is the prime cause 
of the trouble. 

Microscopic investigation has shown that not only in basilar menin- 
gitis may an inflammation be traced from the source of the disease to 
the intraocular end of the nerve, but also in many cases of tumor, the 
focus of inflammation being, perhaps, a localized meningitis or a sur- 
rounding cerebritis. Dr. Gowers points out the frequency of such direct 
inflammatory connection, while he does not deny the well-known ophthal- 
moscopic appearances of mechanical congestion, or swelling of the disc, 
which have given rise to so much confusion in nomenclature. He fur- 
ther Btates, " papillitis may continue slight and without such appearances 
throughout the course of its existence, or they may arise for reasons not 
now definitely known, but not on account of a compression by the scleral 
ring, but from the deposition of inflammatory products within the in- 
flamed nerve-head. The intensity of the process may also be added to 
by the distention of the nerve-sheath, and perhaps, although not yet 
proven, by the admission of the cerebro-spinal fluid, possessing an irri- 
tative quality, within the lymph-spaces of the papilla." This, in the 
author's opinion, best describes, so far as our knowledge goes, the mech- 
anism of optic neuritis, and corresponds with numerous microscopical 
investigations which he has had the privilege of making. 

Elschnig, in a research based upon the post-mortem results of fifty- 
five cases of intracranial disease, shows that the ophthalmoscopic picture 
to which the term "choked disc" is applicable is indicative of an inflam- 
mation of the optic papilla characterized by a high degree of inflamma- 
tory swelling of all its tissues. In no case were well-marked evidences 
of inflammation wanting, and similar changes were found in the trunk 
of the nerve. 

The many varieties of papillitis which occur independently of 
intracranial disease indicate that the optic papilla is a structure 
prone to be inflamed. 

II. Optic-nerve Atrophy. — Under the general term atrophy 
of the optic nerve are included the various types of degeneration 
and shrinking of the fibres of the optic nerve, usually described 
under the subdivision- primary, secondary, consecutive (neuritic 
or pogt-papUMic), and retinal and choroidUze atrophy. The last 
are really forms of consecutive atrophy. 



468 DISEASES OF THE EYE. 

Symptoms. — Certain general symptoms are common to optic- 
nerve atrophy, although these are subject to variations according 
to the clinical types. 

(1) Changes in the Nerve-head, (a) Alterations of the Normal 
Color of the Disc. — The color of the disc varies from a slight gray 
pallor to a pure gray, greenish-gray, or entirely white hue. Many 
intermediate forms of discoloration occur ; thus there may be a 
commingling of gray and red, producing the so-called " gray -red 
disc," and often there is a decided greenish tinge, rarely a blue 
one. 

Much experience is required before deciding that change of 
eolor in the nerve-head is pathological, and a careful considera- 
tion of the age of the patient, the general complexion, the proba- 
ble richness of the blood, the extent of the physiological cup, and 
the character of the illumination must be regarded. Grayness 
of the optic nerve will not always be apparent with ordinary 
methods of examination, especially when present in the deeper 
layers of the disc, but when examined by means of properly re- 
gulated illumination, and through a lens which neutralizes any 
existing error of refraction, this becomes manifest, and the appear- 
ance is then described as "a disc with superficial capillarity, but 
with gray deeper layers." 

It is important to employ both the direct and indirect methods 
of examination, and the concave and plane ophthalmoscopic 
mirror. 

(b) Alteration in the Centre of the Disc. — Sinking of the sur- 
face of the disc, varying from a slight depression to a complete 
excavation (page 367), occurs according to the degree of degene- 
ration which the nerve fibres have experienced. The shape of 
the excavation depends somewhat upon that of the normal phy- 
siological cup, if this has been present. At the bottom of the 
atrophic excavation the mottling of the lamina cribrosa is very 
distinct in some cases of atrophy ; in others, it is not apparent. 

(c) Alterations of flic Margins of the Disc and of the Scleral 
Ring. — In complete atrophy the margin of the optic disc is un- 
usually distinct. In the atrophy which follows a neuritis or 
retinitis, however, the margins are often slightly veiled for a long 
time. 



DISEASES OF THE OPTIC NERVE. 460 

Undue broadening of the .scleral ring indicates shrinking of 
the disc. Even in the early stages of spinal atrophies, the disc 
may be surrounded by a broad scleral ring, which, taken into 
consideration with alteration in the color of the papilla and con- 
traction of the color field (especially red and green), affords 
diagnostic aid in the study of gray degeneration of the optic 
nerve. 

(2) Changes in the Vessels. — In simple atrophy, while there 
may be narrowing of the vessels, this is not always the case, and 
certainly not in the manner seen in consecutive atrophies. Some- 
times the arteries are narrowed and the veins unchanged. 

In neuritic (consecutive) atrophy, the arteries are much con- 
tracted and the veins in contrast are larger than usual, often 
retaining some of the tortuosity which was so marked a feature 
during the papillitic stage. By the contraction of the tissue 
these, too, may later become narrowed. Development of white 
tissue along the course of the vessels, due to thickening of the 
peri-vascular lymph sheath is common in this form of atrophy. 

In retinitic and choroiditic atrophy there is marked contrac- 
tion of both veins and arteries, which at the same time are 
diminished in number. 

(3) Changes in the Surrounding Eye-ground. — The presence of 
alterations in the general fundus depends entirely upon the cause 
of the atrophy. In simple gray and white atrophy such signs 
are absent ; but in post-papillitic and retinitic atrophy spots of 
degeneration, marking the places of former hemorrhages, and 
patches of pigment-heaping, are commonly seen. 

In addition to these ophthalmoscopic changes the following 
symptoms occur : — 

(1) Change in Central Vision. — This varies from a slight de- 
preciation to blindness, and, if the atrophy is bilateral, is more 
marked upon one side than upon the other. In every case, 
where this is possible, especially in early cases or cases of doubt- 
ful atrophy, a neutralization of any exciting refractive error 
should be made before deciding the degree of depreciation of 
central sight. 

(2) Change in the Field of Vision for Form (ichite). — The 
following changes occur : Concentric contraction ; very irregular 



470 



DISEASES OF THE EYE. 



limitations presenting large reentering angles (peripheral scoto- 
mata) ; quadrant-shaped defects ; complete loss of one-half of the 
visual field (hemianopsia) ; and an abnormal blind spot in the 
centre of the field (central scotoma). 



Fig. 145. 




Left eye. Right eye. 

Fields of vision in neuritic atrophy, exhibiting irregular concentric contraction. 

The shading shows where vision was lost. 



The field of vision, concentric restriction being most common, 
does not give evidence of the cause of the atrophy, although it 
may afford information of the localization of the defect ; thus, 
an affection of the macular fibres will produce a central scotoma. 
In spinal atrophy the limitation more frequently begins at the 
outer side than in other situations. 

(3) Change in the Field of Vision for Colors. — There is always 
a defect in color vision. Usually, there is first contraction of the 
green-field, then of the red, and afterwards of the blue and the 
yellow r -field. The confusion and complete loss of central color 
vision occurs in the same way. Exceptions to this statement are 
found, and the perception of red may first feel the influence of 
atrophy. 

Generally the contraction of the color-field is much greater than 
that of the form field (white). (Compare page 375.) Central 



DISEASES OF THE OPTIC NERVE. 



471 



vision may be good, the form field but slightly or not at all 
affected, and yet the green and the red fields may be considerably 
contracted. Hence, the importance of combining all these ex- 
aminations before deciding whether discoloration of the papilla 
is pathological or not. 



Fig. 146. 




Field of vision of the right eye in a case of optic-nerve atrophy. The form 
field is slightly contracted, the color fields markedly restricted. Compare figure 
41. page 89. 

(4) Changes in the Pupil. — The relations of the pupil to the 
action of light depend upon the degree of atrophy. Hence, in 
the majority of cases there is more or less perfect paralytic myd- 
riasis, and when the atrophy is complete the pupil is dilated 
and the iris motionless. Even when the pupil fails to contract 
under the influence of light thrown upon the retina, it may do 
so in the act of convergence. 

If the atrophy is confined to one side, no reaction will occur 
when the light falls upon the corresponding retina, but instant 
contraction takes place when this is directed upon the retina of 
the opposite (unaffected) side. In spinal disease (tabetic atrophy) 
certain changes in the pupil are seen, partly characteristic of this 
affection (page 67). 



472 DISEASES OF THE EYE. 

Varieties of Optic Atrophy. — 1. Primary atrophy (some- 
times called gray, progressive, spinal or tabetic atrophy). — The 
color of the disc is gray or white, sometimes with a greenish or 
bluish tint ; the discoloration is associated with translucency, and 
the stippling of the lamina is evident ; the excavation, if it exists, 
is complete and saucer-like ; the vessels either are smaller than 
normal, especially the arteries, or they are unaffected in size ; the 
edge of the disc is sharply marked, and the scleral ring clean cut 
all around. These symptoms describe the fully formed atrophy. 

In the earlier stages of the degeneration, according to Norris, 
the discs are of a dull-red tint, their capillarity is superficial, and 
the deeper layers, in the neighborhood of the lamina cribrosa, are 
gray and wanting in circulation. There is often sufficient haze of 
the retinal fibres to veil the scleral ring. Later the nerve becomes 
pallid, is somewhat woolly superficially, and is surrounded on 
all sides by a broad and sharply cut scleral ring. The larger 
retinal arteries and veins do not at this stage present any appre- 
ciable change in their calibre or appearance. Both eyes usually 
are affected, one showing a further advance of the degenerative 
process than its fellow. 

2. Secondary Atrophy. — The color of the disc may be gray 
and assume a tint not greatly dissimilar from the atrophy which 
has just been described. In other instances the color is more 
decidedly white. Both sets of vessels may be contracted, usu- 
ally the veins being less affected than the arteries. In a certain 
number of cases of secondary atrophy it is probable that preced- 
ing the degenerative stage there is a transient congestion of the 
discs ; certainly this is true in those cases where there has been a 
retro-ocular neuritis. 

3. Consecutive Atrophy. — (a) Post-papillitic Atrophy. — The 
color of the disc is very gray or white, sometimes with a de- 
cidedly greenish tinge, or even a blue tint. It is noticeable, 
however, that the translucency present in the primary form of 
atrophy is absent, and the stippling of the lamina cribrosa is not 
visible, owing to the existence of a non-transparent tissue which 
covers it. The borders of the disc are slightly veiled, and the 
peri- vascular lymph-sheaths are thickened. The arteries are 



DISEASES OF THE OPTIC NERVE. 473 

contracted, the veins frequently exhibiting distinct tortuosity. 
Retino-choroidal changes are often evident. 

(b) Retinitis and Choroiditis} Atrophy. — This is in the form of 
atrophy of the nerve to which reference has already been made, 
and which follows violent forms of retinitis and choroiditis. 
The color of the disc is characterized by having a distinctly 
yellowish tinge, being somewhat waxy in appearance; its bor- 
ders are not sharply marked ; and the vessels are narrowed, often 
to a great degree. 

( Iauses. — In addition to the forms of atrophy which follow 
inflammation of the nerve (post-pap ill it ic), inflammation of the 
choroid and retina (choroiditic and retinitic atrophy), embolism 
and thrombosis of the central artery and central vein of the 
retina {embolic atrophy), the etiology of those examples that are 
gathered under the general terms primary and secondary atrophy 
require mention. 

Gray degeneration of the optic nerve occurs, in the great ma- 
jority of instances, under the influence of diseases of the spinal 
cord, especially locomotor ataxia. It is frequent in general paral- 
ysis of the insane and insular sclerosis, but less common in 
lateral sclerosis. There is some difference of opinion in regard 
to the frequency of optic atrophy in locomotor ataxia, but an 
average of a number of observations gives 33.7 per cent, of 
atrophies. In most instances it begins in the pre-ataxic stage. 

Primary atrophy has also been ascribed to the influence of cold, 
imperfect nutrition, disturbed menstruation, and venereal excesses. 
There is little doubt that in certain instances it is due to chronic 
malaria, diabetes, syphilis, and the toxic action of certain drugs. 

A very remarkable type of primary atrophy appears to be 
distinctly hereditary, affecting especially the males of a family. 
(Leber, Xorris.) This has been referred to under Optic Neu- 
ritis, because it is probable that in many of the instances 
there is a preceding congestion or low-grade inflammation of the 
disc. 

Finally, there are instances of optic atrophy which can be as- 
cribed to no very definite cause. 

Secondary atrophy appears under the influence of compression 
of the optic tract and the optic fibres ; for instance, by bulging of 



474 DISEASES OF THE EYE. 

the lateral ventricles, pressure of a tumor, exostosis, or aneurism 
(Mitchell) upon the chiasm. It is also said to occur with menin- 
gitis without preceding neuritis. Any compression around the 
optic foramen is likely to produce a secondary atrophy by direct 
injury to the fibres of the optic nerve, just as in other instances 
it may produce a neuritis. 

Blows on the head produce atrophies. This has been noted 
after injuries in the neighborhood of the supraorbital foramen. 
The author has seen two such instances without a fracture of the 
orbital plates; periostitis, however, was probably present. 

Finally, there is a series of atrophies resulting from an inflam- 
mation of the axis of the nerve back of the ball. 

Diagnosis. — The diagnosis of optic-nerve atrophy rests upon 
a consideration of the symptoms already detailed. The student 
is particularly warned not to mistake the pallor of age for the pal- 
lor of disease; not to mistake a large physiological cup, with its 
margin shelving toward the temporal border of the disc, for an 
atrophy confined to half of the optic papilla ; not to mistake a 
posterior staphyloma, which may surround the entire disc, for an 
atrophy ; and not to mistake small patches of retained marrow 
sheath for atrophic changes. 

Not every gray disc, with an unusually marked scleral ring, is 
indicative of atrophy, and it is only when these appearances accord 
with the other manifestations of beginning degeneration that the 
diagnosis of incipient atrophy is justified. 

The differential points between a chronic glaucoma and an 
optic-nerve atrophy have been described (page 379), and also the 
relation of light-sense to optic-nerve atrophy. 

Course and Prognosis. — The course of optic-nerve atrophy 
is always a slow one, lasting for months and it may be years, de- 
pending to a certain extent upon the original cause of the atrophy. 

The prognosis is unfavorable in primary, or, as it is some- 
times called, progressive atrophy, the tendency being to a 
gradual deterioration of sight with shrinkage of the field of 
vision, until complete blindness is the result. The prognosis of 
a consecutive atrophy depends entirely upon the amount of dam- 
age which is likely to ensue from the shrinking which follows 
during the subsidence of the neuritis. In the forms of atrophy 



DISEASES OF THE OPTIC NERVE, 475 

which follow an inflammation of the axis of the nerve, the prog- 
nosis is better. 

In making up a prognosis it is necessary to examine not only 
central vision, but also the field of vision. Sometimes the former 
remains stationary while the latter progressively contracts, and 
under these circumstances false information would be given unless 
both examinations were undertaken. 

Treatment. — This depends upon the cause. If syphilis is 
suspected, the usual remedies are indicated, especially mercuric 
chloride; but mercury is useless in advanced cases, even in syph- 
iliticus. The most generally valuable remedy is strychnine, ad- 
ministered in full doses, preferably by the hypodermic method. 
It may be enforced by nitroglycerine. Other remedies, accord- 
ing to the cause, are iodide of potassium, nitrate of silver, phos- 
phorus, arsenic, iron, santonin, lactate of zinc, hypodermics of an- 
tipyrine (Yalude), and injections of organic liquids. Galvanism 
has been advised, particularly voltaic alternatives (Riggs ; L. W. 
Fox), and good results have been reported. In the author's ex- 
perience galvanism has proved unavailing in true atrophy of the 
optic nerve. Indeed, of the remedies mentioned none have afforded 
more satisfactory results than those usually employed, viz., mercury 
(in suitable cases), the alteratives, strychnia and nitroglycerine, 
and the value of these is limited. In a few instances suspension 
is said to have been followed by improvement in vision in tabetic 
atrophy. 

Orbital Optic Neuritis 1 [Retro-bulbar neuritis ; Centra/ ambly- 
opia; Toxic amblyopia). — In contradistinction to the optic neuritis 
which is specially localized at the intraocular end of the nerve, 
an inflammation occurs in the orbital part of the optic nerve, 
which is called orbital optic neuritis, or retro-bulbar neuritis. It 
appears in an acute and a chronic type. 

(1) Acute Retro-bulbar Neuritis. — The ophthalmoscope reveals 
a moderate degree of retinal congestion and blurring of the edges 
of the optic disc; the arteries are small and the veins enlarged. 

The sight is greatly impaired, and may be so much affected 

1 Dr. Knapp's paper on "Orbital Optic Neuritis, Including Alcohol and 
Tobacco Amaurosis," published in the Archives of Ophthalmology, January, 
1891, has been freely utilized in the preparation of this section. 



476 DISEASES OF THE EYE. 

that there is complete blindness, although this is rare. The 
peripheral field of vision is unaffected, or at least not greatly 
contracted, but there is a central scotoma which may be cither 
positive or negative. Color perception is subnormal. 

Cause. — This affection has been attributed to the influence of 
certain toxic agents such as alcohol, lead, nicotine, etc. ; to men- 
strual disturbances, especially sudden suppression of the menses ; 
to rheumatism ; to measles, diphtheria, scarlet fever and other 
acute infectious diseases ; and to over- work. A certain number 
of cases exist for which no cause can be ascertained. 

The course of the disease may be moderately rapid, or it may 
last for a long time, ending in a restoration of the normal com- 
position of the nerve, or leading to partial or complete atrophy. 
For this reason the prognosis must always be guarded. One or 
both eyes may be affected, and sometimes a long interval occurs 
between the affection of the first and of the second eye. 

Treatment. — The patient must be removed from the in- 
fluence of any supposed cause. If the affection has occurred 
during the course of an acute infectious disease, the treatment 
of this particular malady is indicated. Under other circum- 
stances the best results follow pilocarpine-sweats, full doses of 
salicylic acid, the free use of mercury, and the iodides. 

(2) Chronic Betro-bulbar Neuritis. — This is the form of the 
disease which is very often called tobacco amblyopia, or toxic 
amblyopia. It may not be possible to detect any abnormal 
condition in the face of the optic nerve, or at most only a slight 
veiling of its edges and discoloration of its surface (" dirty-disc"), 
or there is a quadrant-shaped atrophy in the lower and outer part 
of the disc, or finally, if it is at a late stage of the disorder, 
general atrophy. 

Tiie patients complain of diminution of sight which cannot be 
improved by the use of glasses, vision being better in a dull light 
than in the bright glare, owing probably to slight hyperesthesia 
of the retina. 

The color perception is diminished, the peripheral boundaries 
of the visual field are normal, and there is a central color- 
scotoma, especially for red and green, which is usually oval in 
shape, and is situated between the point of fixation and the blind 



DISK ASKS ok THK OPTIC NERVE. 



477 



spot. These colors are not recognized in their true character in 
this area ; green appears dirty white ; red, brownish. Finally the 
scotoma becomes absolute ; i. e., it exists for form. Before decid- 
ing that there is a scotoma for red and green, the examiner should 



Fig. 147. 















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Diagrams illustrating the positions of color-scotomas in the field of vision, 
mapped on a blackboard, in a case of tobacco amblyopia. The continuous line 
indicates the peripheral limits of the form field, the dotted line the red field, 
and the oval dark area the scotoma. 

be sure that there is no red-green blindness. Under these cir- 
cumstances he would be obliged to make use of blue and yellow, 
and under any circumstances it is well to employ these colors in 
the test. 1 

Causes. — In a large majority of the cases just described the 
name "tobacco amblyopia" is justified by the fact that the disease 
occurs for the most part in men whose clinical histories show 
that they have abused tobacco, generally in conjunction with 
alcohol, some observers believing that pure tobacco amblyopia 
does not exist. Certainly in one instance in the author's practice, 
where the scotoma assumed a ring form, there was absolutely no 
history of the use of alcohol. Although usually bilateral, a few 
instances have been recorded in which the symmetrical devel- 



1 Berry has found decided light-sense defect in abnormal states of the macu- 
lar fibres of the optic nerve, and suggests this test as a means of diagnosti- 
cating forms of retro-bulbar neuritis, in which the central scotoma has not 
developed. 



478 DISEASES OF THE EYE. 

opment of tobacco amblyopia has been delayed. It is rare before 
the thirty-fifth year. 

A chronic retro-bulbar neuritis can also be caused by lead, 
carbon bisulphide, iodoform, and opium. It has been attributed 
to syphilis, diabetes, rheumatism, gout, and influenza. 

The pathological lesion which causes this form of amblyopia 
is an interstitial inflammation of the papillo-macular fibres of 
the optic nerve. These fibres, traced by means of their degene- 
ration, consist of a bundle shaped like a triangle near the eye, 
with its base in the lower and outer part of the nerve, and its 
apex at the central vessels. Gradually it passes to the centre of 
the nerve, which it reaches in the optic canal. Finally it can be 
followed into the chiasm and tracts. Retro-bulbar neuritis is 
really a form of peripheral neuritis. 

Couese and Peognosis. — The course is, as its name indicates, 
a chronic one, but the prognosis of the tobacco and alcohol cases 
is good, provided they present themselves at an early enough 
stage for treatment. 

Treatment. — This consists in total abstinence from the use 
of tobacco and alcohol, and in the earlier stages this alone will 
be sufficient to bring about a cure. Later the best remedy is 
strychnia, which, as in other instances of optic nerve disease, 
should be pushed to its full physiological limit. In order to help 
in the absorption of inflammatory products iodide of potash 
may be given; certainly if there is any reason to suspect 
syphilis. In addition to this regulation of diet, rest and an oc- 
casional free diaphoresis are valuable adjuvants. Temporary 
improvement occurs under the influence of inhalations of nitrite 
of amyl, and the circulation of the optic nerve may be stimulated 
by the exhibition of digitalis and mix vomica. 

Injury of the Optic Nerve. — This may occur by the entrance 
of a foreign body into the orbit, like the end of a sharp stick, or 
from a fracture inyolving the bony wall of the orbit or base of 
the skull. Atrophy of the optic nerve is the result. 

Tumors of the Optic Nerve. — These are of rare occurrence, 
according to Finlay about one hundred cases having been recorded, 
and include fibroma, sarcoma, glioma, endothelioma, gumma, 
tubercle, and myxoma. 



DISEASES OP THE OPTIC NERVE. 479 

The symptoms are : Exophthalmos, the eye being pushed down- 
ward and forward, the motions of the globe being unaffected ; and 
defective vision, which is an early manifestation. The growth 
is slow and painless, but sometimes a suppurative keratitis may 
result. The ophthalmoscope reveals distended veins, oedema and 
inflammation of the papilla, followed later by white atrophy and 
shrinking of the vessels. 

TREATMENT. — In eleven instances the tumor has been excised 
without removal of the eyeball, with subsequent loss of the globe 
in four cases, but in most cases enucleation has been necessary, 
the nerve being severed far back so as to include the entire 
growth. Exenteration of the orbit has been performed in four 
ea-es. Among 68 operations, according to Finlay, there were 
eleven relapses and eleven deaths. He advises operative inter- 
ference as soon as the diagnosis is made. 

Hyaline Bodies ( Drusen) in the Papilla. — This affection 
is characterized by the formation in the optic papilla of small 
excrescences, or globular formations, which are sometimes de- 
scribed as colloid masses. The bodies are variously shaped, chiefly 
roundish, of a yellowish-white or bluish-gray color, forming a 
mulberry-like appearance, and presenting a striking ophthalmo- 
scopic picture. They may occur at any age of life, sometimes 
in association with choroido-retinitis, optic neuritis, and optic- 
nerve atrophy, but also in eyes free from other pathological 
changes and with perfectly normal vision. Two views have been 
maintained in regard to the origin of the drusen : (1) That they 
are hyaline excrescences of the lamina vitrea of the choroid 
which become imbedded in the head of the optic nerve, and 
(2) that they have nothing in common with the choroidal excres- 
cences, but are a special pathological process confined to a small 
portion of the optic nerve. The microscopical studies of the 
author indicate that the latter view is the more nearly correct 
of the two. The exact nature of the material thus deposited 
has not been determined. One investigation by Hirschberg and 
Cirincione indicates that the bodies are amorphous and organic, 
and their composition appeared most to resemble that of elastin. 
They may undergo calcification, like the cheesy nodules in the 
lane. 



480 DISEASES OF THE EYE. 



CHAPTEE XVII. 

AMBLYOPIA, AMAUROSIS, AND DISTURBANCES OF VISION 
WITHOUT OPHTHALMOSCOPIC CHANGES. 

Amblyopia and amaurosis both signify dimness of vision, the 
former being used to describe obscurity of sight, and the latter the 
more advanced condition of loss of vision. Although these terms 
are usually applied to cases in which no changes are visible in 
the eye, this limitation is not strictly followed, and eyes blinded 
by inflammatory disease are sometimes described as amaurotic. 1 

Modern methods of examination have greatly lessened the num- 
ber of instances in which the older writers applied the words 
"amblyopia" and "amaurosis." Amblyopia is a symptom and de- 
scribes the defective vision from which the patient suffers. This 
may be due to functional disturbance or to disease of the visual 
apparatus (retina, optic nerve, or visual centres), and may be 
unassociated with changes in the eye-ground ; or there may be 
atrophy of the optic nerve. 

Amblyopia may be congenital or acquired ; temporary or per- 
manent ; and symmetrical or non-symmetrical. 

Congenital Amblyopia — This name is applied to instances of 
defective vision for the most part uncomplicated with fundus 
lesions, although sometimes the papilla is discolored and there is 
a scotoma, either small and absolute, or larger and for colors 
alone. The faulty vision has always existed, and often high 
grades of refractive error, especially hypermetropia and astigma- 
tism, are present, and clear images have never been focused upon 
the retina. Correction of the optical error fails to produce normal 
vision or even nearly normal vision ; the retinal images continue 

! The term amaurosis is also applied to certain cases of blindness in young 
children dependent upon hereditary influence, syphilis, tubercular disease, 
and meningitis. The eye-grounds may or may not be diseased. 



AMBLYOPIA, AMAUROSIS, ETC. 481 

to be defective. In young patients an eye of this character may 
occasionally be trained to mure perfect vision after a proper cor- 
rection of the refractive- error, and this attempt should always 
be made. 1 

Defective vision, attributed to lack of use {amblyopia ex 
anopsia, argamblyopia according to Gould), may occur on account 
of obstruction to the rays of light falling upon the retina; e. g., 
congenital corneal opacities, congenital cataract, and impervious 
persisting pupillary membrane; or in an eye which from earliest 
infancy has squinted, thus not being concerned in the visual act 
(compare with page 533). The amblyopia of a squinting eye 
may disappear, if the seeing eye becomes blind or is removed, 
as in a remarkable case reported by W. B. Johnson. 

Gould maintains that certain cases of amblyopia which have 
been attributed to disuse are really due to a low grade of choroido- 
retinitis affecting the macular region, brought into existence by 
an irritating stimulus with which a long-continued ametropia 
has supplied this area. 

In this category of amblyopias are also placed certain con- 
genital defects of structure; e. g., coloboma of the iris and de- 
ficient development of the entire eye (microphthalmos). Retinal 
hemorrhages in the newly born explain some cases. Usually 
one eye is affected ; if both are amblyopic nystagmus commonly 
is present. Squint may be developed when a single eye is ambly- 
opic. 2 

Congenital Amblyopia for Colors (Color-Bliadness). — Con- 
genital disturbance of the color-sense has been found in about 
3 per cent, of the examinations made for this purpose, but it is 
extremely rare in women (0.2 per cent.). Both eyes, except in 

'A form of amblyopia has been described by Martin and called astigmatic 
amblyopia, dependent upon an imperfect development of the functions of the 
finer anatomical elements of the retina. It has been attributed to the fact that 
at the time of the education of the sense of sight, owing to astigmatism the 
retina lias been asymmetrically stimulated, and consequently there has been 
asymmetry of visual acuity. 

2 A persistent cramp of the lid, such as occurs in children, unrelieved for weeks 
at a time, may produce blindness, noticed when the eyes are finally opened, tem- 
porary in its character with normal ophthalmoscopic appearances. In other cases 
the loss of vision, however, is permanent, with gross changes in the eye-ground. 
This condition has been referred to under blepharospasm 'page 205). 
31 



482 DISEASES OF THE EYE. 

rare instances, are affected, and a distinct hereditary tendency 
has been noted in many instances. In other respects the func- 
tions oi' eyes which are "color-blind" are normal, and the cause 
of the condition has not been determined. 

Derangements of the perception of colors have been divided 
into two varieties : the one characterized by an absence of the 
power to perceive colors, or achromatopsia; and the other cha- 
racterized by difficulty in distinguishing colors, or dyschromaiop- 
sia. The former condition, or color-blindness, is rarely total as 
a congenital defect (a condition which is not uncommon as the 
result of pathological changes in the optic nerve, etc.) ; generally 
it is partial; i. e., one or more of the fundamental colors are not 
recognized. 

According to different theories of the perception of colors, 
partial achromatopsia is divided into green, red, and violet blind- 
ness, or into " red-green" and " blue-yellow blindness," and the 
latter is the more convenient classification. The most usual 
manifestation is red-green blindness, or that in which the indi- 
vidual confuses with a pure green shades of gray and red ; the 
other type, or blue-yellow blindness, is not common. 

In the second variety, or imperfection in the color-sense, 
the individual may correctly recognize brightly marked colors, 
but becomes confused in colors closely allied and in the various 
shades. To him violet and blue, and orange and red, are dif- 
ficult distinctions. Dyschromatopsia should be distinguished 
from partial achromatopsia. (Landolt.) 

The methods of detecting color-blindness have been described 
on page 70. Congenital color-blindness must not be cou- 
founded with the various disturbances of the color-sense which 
result from diseases of the optic nerve and retina, or with those 
which are seen in hysteria. No treatment is of avail. 

Reflex Amblyopia. — Certain cases of partial or complete loss 
of vision have been vaguely attributed to irritations in distant 
portions of the body ; for instance, the presence of parasites in 
the intestinal canal. In many of these instances, however, a 
proper investigation has shown that other causes have been active 
in producing the defective sight. 

A number of well-established cases are on record in which an 



AMBLYOPIA, AMAUROSIS, ETC. 483 

irritation through the branches of the fifth nerve has produced 
an amblyopia, chiefly with disease of the teeth. At all events, 
in any case of amblyopia unattended with ophthalmoscopic 
changes, and not readily classified in any of the groups, a thorough 
examination of the teeth is advisable. 

Traumatic Amblyopia. — This may occur after severe injuries 
to the head, especially in the occipital region ; bruises along the 
course of the spinal curd alter a railroad injury; and blows upon 
the brow in the region of the supraorbital nerve. 

In some of the cases there is either a fracture across the optic 
canal, a hemorrhage into the intracranial cavity, or some disor- 
ganization of the brain contents, followed by secondary changes 
in the optic nerve. In other instances no ophthalmoscopic 
changes are discovered, and the defective vision may be temporary 
in character, or there may be effusion or hemorrhage into the 
intersheath of the optic nerve. Amblyopia after railroad injuries 
is sometimes enormously exaggerated by patients in the hope of 
securing damages. 

The treatment, provided there is no gross lesion such as atrophy, 
hemorrhage, or an cedema of the retina (commotio retin<e.\ is rest 
until there is proper recovery from the injury, and the use of 
strychnia, especially hypodermically. 

Amblyopia and amaurosis occur under the influence of disease 
and the toxic action of certain drugs, due either to a direct effect 
upon the retina, to an influence upon the visual centres, or to 
some change, perhaps of vaso-motor origin, affecting the blood 
supply of these structures. 

In this category may be noticed : — 

(i) Uraemic Amblyopia, or Amaurosis. — This is seen almost 
always with scarlet fever and pregnancy. In scarlet fever it 
appears with albuminuria in the stage of desquamation, and is 
bilateral, the blindness in many cases being absolute and often 
associated with brain-symptoms: convulsions, vomiting, stupor, 
coma, and hemiplegia. In spite of the total blindness a character- 
istic symptom is the preservation of the pupillary reactions. 

The ophthalmoscope picture may be negative, or there is a 
slight neuritis, or a little woolliness of the surface of the optic 
disc. The' prognosis, as far as vi-iou is concerned, is good. 



484 DISEASES OF THE EYE. 

The treatment does not differ from that which is applicable to 
the disease which produced it. 

(2) Glycosuric Amblyopia. — In addition to the affections of 
vision already described in connection with diabetes (cataract and 
retinal hemorrhages), there occurs an amblyopia in this disease 
in which the visual field is sometimes intact, sometimes peri- 
pherally restricted, occasionally hemianopic, but in which there is 
a color-scotoma, and, moreover, in cases not addicted to the use 
of tobacco or alcohol. The amblyopia may be the only symptom 
of diabetes, and in any unexplained case the urine should be ex- 
amined for sugar, a practice which is necessary if color-scotomas 
are found, even if a history of the abuse of tobacco is obtainable. 

The prognosis is unfavorable, and the treatment, which should 
include the usual measures suited to diabetics, is not very effica- 
cious. 1 

(3) Malarial Amblyopia. — In addition to the amblyopia in 
malarial cachexia with lesions apparent at the bottom of the eye- 
grounds, are those cases, without such lesions, due to a special ac- 
tion of the malarial poison upon the optic nerve and the retina. 
These appear in the form of a transient loss of vision, or as complete 
blindness, lasting from several hours to some days or even months. 
The affection disappears under anti-periodic treatment. In most 
of the instances ophthalmoscopic findings are negative, or the 
descriptions are included in vague terms applied to the retina and 
optic nerve — " congestion," " hyperemia," and " redder than 
normal." The affection may be unilateral or bilateral. 

(4) Amblyopia from Loss of Blood. — Loss of sight often fol- 
lows hemorrhage, more frequently when this is spontaneous than 
after a traumatism, and is said to be most complete after hemor- 
rhage from the stomach. 

Two very different results may ensue : Either a temporary 
blindness, owing to the impoverished blood supply of the visual 
centres or retina, or a permanent loss of sight and atrophy of the 
optic nerve. 

'The student interested in the diabetic eye affections should consult Hirsch- 
berg, Deutsch. med. Wochenschrift, March •.'<>. 1891, Moore, N. Y. Medical Jour- 
nal. March 31, 1889, and Dodd, Archiv. of Ophth., vol. xxiv., No. 2. 



AMBLYOPIA, AMAUROSIS, ETC. 485 

The ophthalmoscopic appearances vary from a slight pallor to 
complete atrophic whiteness of the papilla, with contraction of the 
arteries. The lesions in the unfavorable eases usually do not 
appear until a week or more after the hemorrhage has taken place. 
Neuritis, and hemorrhages into the retina, may also arise. The 
prognosis is most favorable in uterine cases. 

The treatment consists in the use of iron, arsenic, and strychnia, 
complete rest and an easily assimilated diet. 1 

Amblyopia from the Abuse of Drugs. — A certain number of 
toxic agents (lead, tobacco, alcohol, etc.) produce an axial neuritis 
with great loss of vision, and these have been described under the 
general term orbital optic neuritis (page 475). 

Amblyopia, more or less complete, may arise under the toxic 
influence of nitrate of silver, mercury, bisulphide of carbon, nitro- 
benzol, salicylic acid, cannabis indica, stramonium, male fern, iodo- 
form, osmic acid, chloral, aud lead. The last agent may produce 
a neuritis, but also an amblyopia without ophthalmoscopic changes. 
It is usually transient, occurs in acute cases, and has been com- 
pared by Gowers to the temporary amaurosis of uraemia. 

The loss of vision which occurs under the influence of quinine 
deserves special mention. It usually is called Quinine Amblyopia, 
or Amaurosis. Although in most instances quinine blindness fol- 
lows the ingestion of a large quantity of the drug, occasionally 
the symptoms appear with moderate doses. The author has seen 
twelve grains produce decided temporary amblyopia in a suscep- 
tible and neurotic woman. 

The characteristic clinical features of quinine amaurosis are 
total blindness subsequent to taking large doses of the drug, ex- 
treme pallor of the optic discs, marked diminution of the retinal 
bloodvessels in number and calibre, and contraction of the field 
of vision. Other symptoms which have been noted are : dimi- 
nution of the color- and light-sense, dilated pupils and immobile 

1 In addition to the amblyopias without ophthalmoscopic changes, seen 
with the diseases already mentioned, others, less commonly observed, could be 
included. For example, sudden blindness with preserved pupillary reaction 
and without ophthalmoscopic changes has been noted with whooping-cough, 
and is probably due to central oedema between the corpora quadrigemina and 
occipital lobes. 



486 DISEASES OP THE EYE. 

iris during the blind stage, and occasionally anaesthesia of the cor- 
nea. Usually the effect of quinine upon the ear is manifested by 
deafness and tinnitus. 

The restoration of central vision may be perfect, or incomplete. 
The contracted field of vision gradually widens out, but does not 
regain its normal limits. The disc may remain pallid and quite 
atrophic-looking years after the poisoning ; in other instances it 
resumes its normal tint. In one case (Gruening) a cherry-colored 
spot was noted in the macula, in another a scotoma in the visual 
field. 

The exact mechanism of quinine blindness is not known, but 
probably depends upon a species of oedema between the optic 
nerve, chiasm, and eyeball, associated with the influence of 
quinine upon the vaso-motor centres, tending to excessive con- 
striction of the peripheral circulation, and the final production of 
local changes in the vessels (endo-vasculitis). The author has 
experimentally shown that toxic doses of quinine in dogs may 
cause permanent optic atrophy and thrombosis of the central vein 
of the retina. 

The treatment, in addition to the discontinuance of the drug, 
consists in the administration of nitrite of amy], which will 
cause temporary improvement, and the exhibition of strychnia 
and digitalis. 

Hysterical Amblyopia. — Hysterical blindness usually occurs 
in young girls and women ; but both males and females may be 
affected. The loss of vision is complete, almost always mono- 
lateral, and the pupil reacts promptly to light when the sound 
eye is covered. The ophthalmoscopic appearances are normal. 
Quite commonly it is possible to prove by the usual tests that 
the supposed blind eye really sees (page 487). 

In addition to monocular blindness there is a large group of 
cases in which achromatopsia or dyschromatopsia, contraction of 
the field of vision, and hemianesthesia constitute the symptoms. 
Sometimes, instead of simple contraction of the field of vision, 
there is hemianopsia; rarely scotoma. The defect of vision may 
occur in the form of crossed amblyopia, i. e., complete or partial 
blindness on the same side as the hemianesthesia, and associated 
with some deficiency of acuity of vision upon the opposite side. 



AMBLYOPIA, AMAUROSIS, ETC. 487 

No! only may there be partial or complete color blindness in 

hysteria, but also a mure or less perfect reversal of the order of 
the colors as they normally appear. In a series of eases studied 
by Dr. John K. Mitchell and the author, this phenomenon was 
well shown. No other ocular manifestations were present. 

Hysteria produces many other remarkable functional disturb- 
ances of the eye — monocular diplopia, ptosis, blepharospasm, 
conjugate deviation of the eyes, and the great symptom-group 
gathered under the term "retinal asthenopia" — which do not 
properly belong to this category. 

The prognosis of these cases in the main is good, although the 
blindness may last for long periods of time. 

The treatment consists of measures calculated to improve the 
condition of the patient, massage, rest, electricity, and tonics. 

Pretended Amblyopia [Malingering). — For the purpose of 
escaping irksome duties, for example in the army, or to excite 
sympathy, patients will occasionally pretend to be blind in one 
eye. In order to detect the deception many plans have been 
originated. Two methods will be described : — 

(1) The Diplopia Test. — This is performed in the same 
manner as the ordinary examinations of the external ocular mus- 
cles with prisms. The subject is seated before a lighted candle 
at twenty feet distance, and a 7° prism placed before the admit- 
tedly sound eye. If, now, superimposed double images are 
acknowledged, there is binocular vision, and the fraud is de- 
tected. The examiner may vary the test by placing the prism 
before the supposed blind eye, either base up or base down. 

(2) Harlan's Test. — This is an extremely useful and simple 
device, and is performed as follows : Place an ordinary trial 
frame upon the subject's face and put before the admittedly 
sound eye a high convex glass (4-16 D), and before the eye 
which is claimed to be blind a plain glass or a weak concave 
spherical ( — 25 D), which will not interfere with vision. If 
letters placed at a distance of six metres are read, the act of 
reading must have been done by the eye which was claimed 
to be sightless, inasmuch as vision at that distance with the other 
eye is excluded by the presence of the high convex lens. The 
test may be further elaborated by covering the pretended blind 



488 DISEASES OF THE EYE. 

eye and requesting the patient to read the letters ; if he is unable 
to do so, the fraud is at once exposed. 

If a malingerer claims to be blind in both eyes these tests will 
not avail, and he can be detected only by placing a careful watch 
over him. The fact that the pupil contracts on exposure to light 
does not prove that there is sight in the eye, because, as Swanzy 
points out, a lesion in the centre of vision, or in the course of 
the fibres connecting this centre with the corpora quadrigemina, 
producing absolute blindness, would still permit a perfect reaction 
of the pupil to light. 

Night-blindness (Functional night-blindness ; often incorrectly 
termed hemeralopia, but properly nyctalopia). — It has already 
been pointed out that night-blindness is one of the early symp- 
toms of pigmentary degeneration of the retina. In the present 
condition, however, there are no retinal lesions. 

It is a functional complaint, consisting in a diminished sensi- 
bility or imperfect adaptation power of the retina (Treitel), due, 
apparently, to exposure of the eye to strong light, together with 
a debilitated and often scorbutic state of the system. It affects 
residents in tropical countries, often soldiers and sailors, and has 
been occasionally observed in large schools, usually in the early 
spring or summer (Nettleship, Snell). It prevails as an endemic 
in certain countries, especially in Russia during the Lenten fasts. 
Adam tick disputes the influence of fasts and attributes the disease 
to miasmatic parasites. 

The patients, in addition to their inability to see well in the 
dusk or even on dull days, although their vision is good enough 
in a bright light, often suffer from one of the forms of xerosis 
conjunctivae (epithelial xerophthalmos, see page 249). 

Treatment. — This includes the administration of iron, 
quinine, strychnia, and cod-liver oil, according to the indications. 
Dark-colored glasses should be worn. If scurvy is present, the 
diet and remedies suited to this condition should be prescribed. 

Day-blindness (often incorrectly termed nyctalopia, but prop- 
erly named hemeralopia). — This is an affection, or rather a symp- 
tom, as the name implies, characterized by the fact that its sub- 
jects see better on dull days and in the dark than in a bright 
light. The visual field is not concentrically contracted. 



AMBLYOPIA, AMAUROSIS, ETC. |S!» 

This Bymptom occurs with the condition described by Arlt as 
retinitis nyctalopia, and with orbital optic neuritis of the chronic 
type (tobacco amblyopia, page 476). It also occurs in other 
affections of the optic nerve and in some diseases of the retina. 

The same condition may be present with certain congenital ano- 
malies — albinism, coloboma of the iris, and irideraemia. It also 
occurs as an idiopathic affection, and may develop in those who 
have long been excluded from the light. It mav also be con- 
genital, and may be associated with an amblyopia of like origin. 

A tonic treatment should be tried aud the retina gradually 
educated to sustain bright light. 

Snow Blindness. — As this ordinarily is seen in northern 
regions, it is an affection of the conjunctiva. There are burning 
paiu, photophobia, blepharospasm, hyperemia of the conjunctiva, 
and chemosis. In severe cases there may be ulceration of the 
cornea. The pupils are small, and there is congestion of the 
retina. The visual acuity may be unaffected, or it may be dis- 
tinctly lessened, especially if corneal complication or a scotoma 
coexists. The dazzling of the snow may cause restriction of the 
field of vision, scotoma, and night-blindness, 1 but when the sun 
shines, the heat reflected from the surface of the snow produces 
an erythema of the conjunctiva. If the sunshine is absent, a 
mechanical cause is found in small flying particles of snow and 
ice (A. Berlin). Prolonged exposure to powerful electric light 
may produce analogous symptoms — electric ophthalmia. 

Erythropsia, or Red Vision. — Colored vision in glaucoma 
(iridescent vision), in the form of variously tinted halos about 
the lamp lights, has been described, and patients with blind eyes 
occasionally complain of being conscious of colored lights, owing 
probably to some irritation of the visual centres. 

Erythropsia in most instances has been noted after cataract 
extraction. Visual acuity is not affected, but everything appears 
of a red or violet color. Bromide of potash is indicated, and is 
said to ameliorate the symptom. 

Micropsia and Megalopsia have been described in connection 
with syphilitic retinitis. They may appear as a functional dis- 
order in hysterical cases. 

1 The opposite condition, day-blindness, has been reported. 



490 DISEASES OF THE EYE. 



CHAPTER XVIII. 

AMBLYOPIA OF THE VISUAL FIELD, SCOTOMAS AND 
HEMIANOPSIA. 

The importance of perimetric measurements in the study of 
various forms of ocular disease, especially in glaucoma and in 
affections of the retina, choroid, and optic nerve, has been noted. 
(For the methods of examination consult Chapter II.) There re- 
main to be considered certain conditions in which a defect in the 
field of vision constitutes one of the most prominent symptoms. 

I. Partial Fugacious Amaurosis (" Flimmer-scotom"). — The 
symptoms are : A sense of vertigo ; a positive darkeniug of the 
field of vision of each eye, beginning at the centre and widening 
out in a vibratory movement until it overspreads the field, with 
corresponding sinking of the central acuity of sight ; and cessa- 
tion of the amaurosis with the onset of headache aud vomiting. 
It may then be a prodrome of hemicrania, but is also seen with- 
out it, and may occur in syphilitic subjects. The condition pro- 
bably depends upon circulatory disturbances in the occipital lobes. 

The treatment is directed toward the headache, the partial 
amaurosis being exceedingly temporary in character, and includes 
the measures suited to migraine. Syphilis calls for the usual 
remedies. 

II. Amblyopia of the Visual Field (Anaesthesia refiner). — This 
functional disturbance as part of a general neurosis has been 
described on page 419. Because of the peculiar changes in the 
visual field many authors prefer the name "amblyopia of t lie 
visual field" to that of "anaesthesia of the retina." 

Somewhat analogous restrictions of the visual field are seen 
after injuries, and with traumatic anaesthesia of the retina ; in the 
latter condition the element of hysteria cannot always be elimi- 
nated. 



AMBLYOPIA OF THE VISUAL FIELD. I'M 

III. Scotomas. — Any lesion which blots out the function of a 
portion of the retina produces a corresponding blind ana in the 
Held of vision, or a scotoma, for example a hemorrhage, a patch 
of retino-choroiditis in the macular region, or spots of dissemi- 
nated choroiditis in the periphery of the eye-ground. Papillitis 
causes an enlargement of the natural blind spot. (Consult 
figure 143). In chronic glaucoma, scotomas may lie in the 
centre of the field, or at its more peripheral parts, and sometimes 
assume a ring shape. Unilateral scotomas may occur in hys- 
teria, with menstrual disorders, in partial embolism of the central 
artery of the retina, and with disease of the macular cortical centre. 

In addition to these diseases certain affections of the optic 
nerve are accompanied by a scotoma. 

Following the classification of Jensen, these may be described 
as : — l 

(a) Central Amblyopia with Scotoma [Toxic Amblyopia). — This 
affection has been described on page 475. 

(b) Stationary Optic Atrophy, with Scotoma. — This is charac- 
terized by a scotoma, similar to the one which occurs with toxic 
amblyopia, but much more decided. There are marked diminution 
of central vision, a depreciation of the color sense, and ophthalmo- 
scopically the appearances of optic-nerve atrophy. The process is 
stationary, and vision does not improve under treatment. Jensen 
finds this affection exclusively in men before their thirty-fourth 
year. It has a hereditary tendency, and is said to be caused by 
exhaustion and lack of sleep. Sometimes no cause can be demon- 
strated. Preceding the atrophy there may be slight neuritis. 

In the cases of hereditary atrophy of the optic nerve recorded 
by W. F. Norris, the ophthalmoscopic changes commenced with a 
stage of cloudy swelling of the disc and passed on to a gradual 
death of the nerve. The disease began with a central scotoma, 
first for color, but gradually this became complete. Both the 
males and females of the family were affected. 

(c) Progressive Optic Atrophy, with Scotoma. — This includes the 
class of cases in which the optic-nerve atrophy of spinal disease 

1 A translation by Dr. G. A. Berry of a lengthy abstract of Jensen's article 
on " Diseases of the Eye accompanied by a Central Scotoma" appears in the 
Ophthalmic Review, January, 1891. 



492 DISEASES OF THE EYE. 

(tabes dorsalis and disseminated sclerosis) is associated with a 
scotoma. The scotoma is central and shaped like the one iu 
tobacco amblyopia, but as the disease progresses the peripheral 
field contracts, and finally it becomes difficult to detect the cen- 
tral defect. It is not common to find a central scotoma in tabetic 
atrophy of the optic nerve, but more frequent in insular sclerosis. 

(d) Optic Neuritis, u-ith Scotoma. — An unusual symptom of 
intraocular neuritis ca